uboot-rockchip: add dedicated uboot for LinkEase EasePi R1

uboot-rockchip: add dedicated uboot for LinkEase EasePi R1

The generic-rk3568 does not reset the gmac phy, causing the kernel to
fail to initialize gmac during cold boot with the error message
"mdio_bus stmmac-1: MDIO device at address 1 is missing."

Adding a dedicated uboot for EasePi R1 to resolve this issue.

The EasePi R1's DTS hasn't been merged into the Linux release yet,
so it cannot be submitted to the upstream u-boot.

Fixes: ef093299db ("uboot-rockchip: add support for LinkEase EasePi R1")
Signed-off-by: Liangbin Lian <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20772
Signed-off-by: Hauke Mehrtens <[email protected]>