mixtile-blade3: u-boot: join rockchip-rk3588's default u-boot-radxa-rk35xx scheme

- rebased 3 patches
- moved null patches for dts & defconfigs to `dt` / `defconfig` dirs
- don't rename defconfigs: those are shared with Joshua Riek (ubuntu-rockchip)
- defconfigs re-saved

Author: rpardini

config/boards/mixtile-blade3.csc

@@ -4,21 +4,16 @@ declare -g BOARDFAMILY="rockchip-rk3588"
 declare -g BOARD_MAINTAINER="rpardini"
 declare -g KERNEL_TARGET="vendor,edge"
 declare -g BOOT_FDT_FILE="rockchip/rk3588-blade3-v101-linux.dtb" # Included in https://github.com/armbian/linux-rockchip/pull/64 # has a hook to change it for edge below
-
-declare -g BOOT_SCENARIO="spl-blobs" # so we don't depend on defconfig naming convention
-declare -g BOOT_SOC="rk3588"         # so we don't depend on defconfig naming convention
-declare -g BOOTCONFIG="blade3_defconfig"
+declare -g BOOT_SCENARIO="spl-blobs"                             # so we don't depend on defconfig naming convention
+declare -g BOOT_SOC="rk3588"                                     # so we don't depend on defconfig naming convention
+declare -g BOOTCONFIG="blade3_defconfig"                         # there is also blade3_sata_defconfig available
 declare -g IMAGE_PARTITION_TABLE="gpt"
 declare -g UEFI_EDK2_BOARD_ID="blade3" # This _only_ used for uefi-edk2-rk3588 extension
 
-function post_family_config__uboot_mixtile() {
-	display_alert "$BOARD" "Configuring Mixtile u-boot" "info"
-	declare -g BOOTSOURCE='https://github.com/radxa/u-boot.git'
-	declare -g BOOTBRANCH='branch:next-dev-v2024.03'
-	declare -g OVERLAY_PREFIX='rockchip-rk3588'
-	declare -g BOOTDIR="u-boot-${BOARD}"                   # do not share u-boot directory
-	declare -g BOOTPATCHDIR="legacy/u-boot-mixtile-rk3588" # Few patches in there; defconfig & PD hacks
-	declare -g BOOTDELAY=1                                 # build injects this into u-boot config. we can then get into UMS mode and avoid the whole rockusb/rkdeveloptool thing
+# Vendor u-boot; use the default family (rockchip-rk3588) u-boot. See config/sources/families/rockchip-rk3588.conf
+function post_family_config__vendor_uboot_mekotronics() {
+	display_alert "$BOARD" "Configuring $BOARD vendor u-boot" "info"
+	declare -g BOOTDELAY=1 # build injects this into u-boot config. we can then get into UMS mode and avoid the whole rockusb/rkdeveloptool thing
 }
 
 function post_family_config_branch_edge__different_dtb_for_edge() {