wifi: mt76: mt7996: enable mesh HW amsdu/de-amsdu support

This enables HW offloading amsdu/de-amsdu support for 802.11s mesh
interface.

Co-developed-by: Bo Jiao <bo.jiao@mediatek.com>
Signed-off-by: Bo Jiao <bo.jiao@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>