[][MAC80211][misc][Add MT7996 external openwrt build]

[Description]
Add MT7996 trunk Firmware (20230302)

[Release-log]
N/A

Change-Id: I17eb7971d2060d1743e104cde990fe5056243efe
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7227778
7 files changed