rock-5b: add initial radxa rock-5b .wip (#4026)

* rock-5b: add initial raxda rock-5b .wip (by @amazingfate); vendor u-boot & kernel

- .wip board
- using BOARDFAMILY `rk35xx`, which was for rock-3a
- patch by @piter75 uboot for working 'source' command so boot.scr can be used, and not extlinux
- .config: hammer CONFIG_JOYSTICK_XPAD & CONFIG_JOYSTICK_PSXPAD_SPI
- rock5 add kernel optiions by @lanefu
- disable CONFIG_LOCALVERSION_AUTO otherwise packaging goes insane
- make its kernel is own LINUXFAMILY to as to not mess up rock-3a
- CONFIG_VT=y & SKIP_BOOTSPLASH="yes"

* Add separate family for rock 5b - rockchip-rk3588

Co-authored-by: amazingfate <liujianfeng1994@gmail.com>
Co-authored-by: root <catalinii@yahoo.com>

config/boards/rock-5b.wip

@@ -0,0 +1,13 @@
+# Radxa RK3588 SoC
+BOARD_NAME="Rock 5B"
+BOARDFAMILY="rockchip-rk3588"
+BOOTCONFIG="rock-5b-rk3588_defconfig"
+KERNEL_TARGET="legacy"
+FULL_DESKTOP="yes"
+BOOT_LOGO="desktop"
+BOOT_FDT_FILE="rockchip/rk3588-rock-5b.dtb"
+BOOT_SCENARIO="spl-blobs"
+WIREGUARD="no"
+BOOT_SUPPORT_SPI="yes"
+IMAGE_PARTITION_TABLE="gpt"
+SKIP_BOOTSPLASH="yes" # Skip boot splash patch, conflicts with CONFIG_VT=yes