mt76: mt7921: Add mt7922 support

Add new chip mt7922 in mt7921 module with following items
1. new chip ID / fw bin name
2. is_mt7922()
	check chip type for different fw files
3. mt7921_get_data_mode()
	check security type of fw (backward compatible)

Co-developed-by: Jimmy Hu <Jimmy.Hu@mediatek.com>
Signed-off-by: Jimmy Hu <Jimmy.Hu@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>