wifi: mt76: sdio: fix transmitting packet hangs

Fix transmitting packets hangs with continuing to pull the pending packet
from mac80211 queues when receiving Tx status notification from the device.

Fixes: aac5104b

 ("mt76: sdio: do not run mt76_txq_schedule directly")
Acked-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: YN Chen <yn.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>