Makefile: Use -polly-invariant-load-hoisting if CLANG < 16

A recent clang 16 update has broken the functionality of
`-polly-invariant-load-hoisting` and fails compilation when kernel
is compiled with full LTO, causing the following backtrace:

PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: clang -Wp,-MD,drivers/md/.md.o.d -nostdinc -isystem /tmp/cirrus-ci-build/toolchains/clang/lib/clang/16.0.0/include -I../arch/arm64/include -I./arch/arm64/include/generated -I../include -I./include -I../arch/arm64/include/uapi -I./arch/arm64/include/generated/uapi -I../include/uapi -I./include/generated/uapi -include ../include/linux/kconfig.h -include ../include/linux/compiler_types.h -I../drivers/md -Idrivers/md -D__KERNEL__ -mlittle-endian -DKASAN_SHADOW_SCALE_SHIFT=3 -Qunused-arguments -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -Werror-implicit-function-declaration -Werror=return-type -Wno-format-security -std=gnu89 --target=aarch64-linux-gnu --prefix=/tmp/cirrus-ci-build/Kernel/../toolchains/clang/bin/aarch64-linux-gnu- --gcc-toolchain=/tmp/cirrus-ci-build/toolchains/clang -Wno-misleading-indentation -Wno-bool-operation -Werror=unknown-warning-option -Wno-unsequenced -opaque-pointers -fno-PIE -mgeneral-regs-only -DCONFIG_AS_LSE=1 -fno-asynchronous-unwind-tables -Wno-psabi -DKASAN_SHADOW_SCALE_SHIFT=3 -fno-delete-null-pointer-checks -Wno-frame-address -Wno-int-in-bool-context -Wno-address-of-packed-member -O3 -march=armv8.1-a+crypto+fp16+rcpc -mtune=cortex-a53 -mllvm -polly -mllvm -polly-ast-use-context -mllvm -polly-detect-keep-going -mllvm -polly-invariant-load-hoisting -mllvm -polly-run-inliner -mllvm -polly-vectorizer=stripmine -mllvm -polly-loopfusion-greedy=1 -mllvm -polly-reschedule=1 -mllvm -polly-postopts=1 -fstack-protector-strong --target=aarch64-linux-gnu --gcc-toolchain=/tmp/cirrus-ci-build/toolchains/clang -meabi gnu -Wno-format-invalid-specifier -Wno-gnu -Wno-duplicate-decl-specifier -Wno-asm-operand-widths -Wno-initializer-overrides -Wno-tautological-constant-out-of-range-compare -Wno-tautological-compare -mno-global-merge -Wno-void-ptr-dereference -Wno-unused-but-set-variable -Wno-unused-const-variable -fno-omit-frame-pointer -fno-optimize-sibling-calls -Wvla -flto -fwhole-program-vtables -fvisibility=hidden -Wdeclaration-after-statement -Wno-pointer-sign -Wno-array-bounds -fno-strict-overflow -fno-stack-check -Werror=implicit-int -Werror=strict-prototypes -Werror=date-time -Werror=incompatible-pointer-types -fmacro-prefix-map=../= -Wno-initializer-overrides -Wno-unused-value -Wno-format -Wno-sign-compare -Wno-format-zero-length -Wno-uninitialized -Wno-pointer-to-enum-cast -Wno-unaligned-access -DKBUILD_BASENAME=\"md\" -DKBUILD_MODNAME=\"md_mod\" -D__KBUILD_MODNAME=kmod_md_mod -c -o drivers/md/md.o ../drivers/md/md.c
1.	<eof> parser at end of file
2.	Optimizer
  CC      drivers/media/platform/msm/camera_v2/camera/camera.o
  AR      drivers/media/pci/intel/ipu3/built-in.a
  CC      drivers/md/dm-linear.o
 #0 0x0000559d3527073f (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x3a7073f)
 raystef66#1 0x0000559d352705bf (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x3a705bf)
 raystef66#2 0x0000559d3523b198 (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x3a3b198)
 raystef66#3 0x0000559d3523b33e (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x3a3b33e)
 raystef66#4 0x00007f339dc3ea00 (/usr/lib/libc.so.6+0x38a00)
 raystef66#5 0x0000559d35affccf (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x42ffccf)
 raystef66#6 0x0000559d35b01710 (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x4301710)
 raystef66#7 0x0000559d35b01a12 (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x4301a12)
 raystef66#8 0x0000559d35b09a9e (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x4309a9e)
 raystef66#9 0x0000559d35b14707 (/tmp/cirrus-ci-build/toolchains/clang/bin/clang-16+0x4314707)
clang-16: error: clang frontend command failed with exit code 139 (use -v to see invocation)
Neutron clang version 16.0.0 (https://github.com/llvm/llvm-project.git 598f5275c16049b1e1b5bc934cbde447a82d485e)
Target: aarch64-unknown-linux-gnu
Thread model: posix
InstalledDir: /tmp/cirrus-ci-build/Kernel/../toolchains/clang/bin

Therefore, move `-polly-invariant-load-hoisting` to the bottom and use
it conditionally when clang < 16.
This is to be noted that a condition for LTO has not been used here
specifically since the broken polly flag can harm the binaries regardless
of the usage of LTO in some unwanted scenarios and ways. Additionally,
if we conditionally use polly for LTO only, or with LTO and Clang < 16
condition, old compilers will not be able to use the flag without LTO
at all. Therefore, just abandon this flag entirely for clang >= 16.

Signed-off-by: Tashfin Shakeer Rhythm <tashfinshakeerrhythm@gmail.com>

Makefile

@@ -711,10 +711,13 @@ ifdef CONFIG_POLLY_CLANG
 POLLY_FLAGS	+= -mllvm -polly \
 		   -mllvm -polly-ast-use-context \
 		   -mllvm -polly-detect-keep-going \
-		   -mllvm -polly-invariant-load-hoisting \
 		   -mllvm -polly-run-inliner \
 		   -mllvm -polly-vectorizer=stripmine
 
+ifeq ($(shell test $(CONFIG_CLANG_VERSION) -lt 160000; echo $$?),0)
+POLLY_FLAGS	+= -mllvm -polly-invariant-load-hoisting
+endif
+
 ifeq ($(shell test $(CONFIG_CLANG_VERSION) -gt 130000; echo $$?),0)
 POLLY_FLAGS	+= -mllvm -polly-loopfusion-greedy=1 \
 	     -mllvm -polly-reschedule=1 \