mt76: mt7615: switch mt7615_mcu_set_tx_ba to v2 format

To adapt new firmware version.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Tested-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>