Added USB boot support and eMMC r/w fixes for RK3528.
Refreshed upstreamed patches while at it.
Signed-off-by: Tianling Shen <cnsztl@immortalwrt.org>
Link: https://github.com/openwrt/openwrt/pull/20375
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
