wifi: mt76: mt7925: pass mlink to mcu_sta_update()

wifi: mt76: mt7925: pass mlink to mcu_sta_update()

Drop the mt792x_sta_to_link() lookup in mt7925_mcu_sta_update() and
pass the resolved mlink from the caller instead. The link context is
already known at the call site, making the lookup redundant.

This keeps the helper lookup-free and makes WCID selection explicit.

No functional change intended.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Link: https://patch.msgid.link/20260306232238.2039675-5-sean.wang@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>