wifi: mt76: mt7921: add auto regdomain switch support

Implement 802.11d-based automatic regulatory domain switching to
dynamically determine the regulatory domain at runtime.

The scan-done event structure by reusing reserved padding and appending
new fields; the layout and values remains backward-compatible with
existing users.

Co-developed-by: Sean Wang <[email protected]>
Signed-off-by: Sean Wang <[email protected]>
Signed-off-by: JB Tsai <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Felix Fietkau <[email protected]>

mt7921/mac.c

@@ -7,6 +7,7 @@
 #include "mt7921.h"
 #include "../dma.h"
 #include "../mt76_connac2_mac.h"
+#include "regd.h"
 #include "mcu.h"
 
 #define MT_WTBL_TXRX_CAP_RATE_OFFSET	7
@@ -699,6 +700,8 @@ void mt7921_mac_reset_work(struct work_struct *work)
 					    IEEE80211_IFACE_ITER_RESUME_ALL,
 					    mt7921_vif_connect_iter, NULL);
 	mt76_connac_power_save_sched(&dev->mt76.phy, pm);
+
+	mt7921_regd_change(&dev->phy, "00");
 }
 
 void mt7921_coredump_work(struct work_struct *work)