Remove cast-align for RISC-V

Fix #2836.

Signed-off-by: Steven Bellock <sbellock@nvidia.com>

CMakeLists.txt

@@ -215,7 +215,10 @@ if(CMAKE_SYSTEM_NAME MATCHES "Linux")
 
     if(TOOLCHAIN STREQUAL "GCC")
         set(CMAKE_C_COMPILER gcc)
-        add_compile_options(-std=c99 -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -ffunction-sections -fdata-sections -fno-common -Wno-address -fpie -fno-asynchronous-unwind-tables -DUSING_LTO  -Wno-maybe-uninitialized -Wno-uninitialized  -Wno-builtin-declaration-mismatch -Wno-nonnull-compare -Werror-implicit-function-declaration -Wcast-qual -Wcast-align)
+        add_compile_options(-std=c99 -fshort-wchar -fno-strict-aliasing -Wall -Werror -Wno-array-bounds -ffunction-sections -fdata-sections -fno-common -Wno-address -fpie -fno-asynchronous-unwind-tables -DUSING_LTO  -Wno-maybe-uninitialized -Wno-uninitialized  -Wno-builtin-declaration-mismatch -Wno-nonnull-compare -Werror-implicit-function-declaration -Wcast-qual)
+        if (NOT ARCH STREQUAL "riscv32" AND "riscv64")
+            add_compile_options(-Wcast-align)
+        endif()
         if (ARCH STREQUAL "x64")
             add_compile_options(-mno-red-zone)
         endif()