Adding OpenWrt support for Xiaomi "Redmi Router AX6S"/"Xiaomi Router AX3200"

[Dingus]

Adding OpenWrt support for Xiaomi AX3600 (Part 1)

...which is presumably IPQ8071. More information expected during during Mi 10 launch on Feb 13th. I hope we will get relatively affordable high-end device which has good chances of being supported by OpenWRT.