rockchip-rk3588: drop BOOTFS_TYPE for single root partition image

[amazingfate]

Description

I guess all these BOOTFS_TYPE come from #3874. Rock3a and other rk356x boards uses an old version of vendor u-boot: https://github.com/radxa/u-boot/tree/stable-4.19-rock3, which has bad support for ext4 filesystem. While rk3588 uses new version of vendor u-boot which doesn't have ext4 partition issue, so I just drop all this config from rk3588 boards.
Command to query boards with this config:

grep -rn rockchip-rk3588 config/boards/|awk -F ':' '{print $1}'|xargs grep BOOTFS_TYPE

Here are the vendor uboot source of these boards:

board	vendor uboot source
armsom-sige7 armsom-w3 nanopc-cm3588-nas nanopct6 nanopi-r6s rock-5b	https://github.com/radxa/u-boot/tree/next-dev-v2024.03
fxblox-rk1	https://github.com/functionland/u-boot/tree/next-dev
indiedroid-nova	https://github.com/stvhay/u-boot/tree/rockchip-rk3588-unified
orangepi5-plus orangepi5pro	https://github.com/orangepi-xunlong/u-boot-orangepi/tree/v2017.09-rk3588
orangepi5	https://github.com/u-boot/u-boot/tree/2f0282922b2c458eea7f85c500a948a587437b63

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also note any relevant details for your test configuration.

• ./compile.sh build BOARD=rock-5b BRANCH=vendor BUILD_DESKTOP=yes BUILD_MINIMAL=no DEB_COMPRESS=xz DESKTOP_ENVIRONMENT=gnome DESKTOP_ENVIRONMENT_CONFIG_NAME=config_base ENABLE_EXTENSIONS='rk-panthor mesa-oibaf rk-multimedia-amazingfate' KERNEL_CONFIGURE=no KERNEL_GIT=shallow RELEASE=noble

Checklist:

Please delete options that are not relevant.

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules