WARNING: "cfg80211_mgmt_tx_status" [/home/ai7688/1215_ko/rtl8822BU/88x2bu.ko] undefined!
WARNING: "ieee80211_frequency_to_channel" [/home/ai7688/1215_ko/rtl8822BU/88x2bu.ko] undefined!
WARNING: "cfg80211_rx_mgmt" [/home/ai7688/1215_ko/rtl8822BU/88x2bu.ko] undefined!

Makefile add below:

KBUILD_EXTRA_SYMBOLS="/home/ai7688/1208/AI7688H_OpenWRT_Build_FW_Setting_Tool_V1.0/openwrt/build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7688/compat-wireless-2016-01-10/Module.symvers"


or


KBUILD_EXTMOD="/home/ai7688/1208/AI7688H_OpenWRT_Build_FW_Setting_Tool_V1.0/openwrt/build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7688/compat-wireless-2016-01-10/"