Adding OpenWrt support for Xiaomi AX3600 (Part 1)

Thanks for pointing that out, It's exactly the same issue fixed in x3600 roaming issue thread:

The script solves the issue we have with multiple APs and fixed MAC in wireless clients in 5.15 build.

From what I read in the above linked thread, qca-nss-drv-bridge-mgr needs to be included and now ported to the new kernel. I tried to build it but had some errors.