OpenWrt support for Xiaomi AX3000T

[alexq]

@RHBH

This information should be added to the wiki in "change to openwrt u-boot"

"Warning, winbond flash is not compatible with openwrt U-Boot".

Good point!
But are there any other hardware that should be mentioned in the warning for official OpenWrt U-Boot ( Change to OpenWrt U-Boot section) ?

1. Winbond NAND, 2. AN8855 switch, ... what else?