wifi: mt76: mt7921: introduce CSA support

Add CSA (Channel Switch Announcement) related implementation
in collaboration with mac80211 to deal with dynamic channel
switching.

Signed-off-by: Leon Yen <leon.yen@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Link: https://patch.msgid.link/20241107061440.6545-1-mingyen.hsieh@mediatek.com


Signed-off-by: Felix Fietkau <nbd@nbd.name>