mt76: mt7663s: introduce WoW support via GPIO

SDIO-based WiFi would rely on an additional GPIO pin to wake up the host.

Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>