Adding OpenWrt support for Xiaomi AX3600 (Part 1)

@robimarko
I noticed that the interfaces wlan1, wlan2, changed their names to phy1-ap0, phy2-ap0:
image
ip link show

7: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
10: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
11: phy1-ap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br-lan state UP qlen 4096
12: phy2-ap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master br-lan state UP qlen 4096