wifi: mt76: mt7925: add mt7925_set_link_key

add mt7925_set_link_key to set up the key according to the link id

Co-developed-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Co-developed-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Link: https://patch.msgid.link/e8cd7d37484be238a4eb9e500ef2b8aa46e43667.1720248331.git.sean.wang@kernel.org


Signed-off-by: Felix Fietkau <nbd@nbd.name>