wifi: mt76: mt7925: move WCID teardown into link_sta_remove()

wifi: mt76: mt7925: move WCID teardown into link_sta_remove()

Move WCID teardown into mt7925_mac_link_sta_remove() to mirror the
dev->mt76.wcid[] publish done during link add.

This clears the published WCID before the rest of teardown, so WCID
lookups no longer expose a link that is being removed.

No functional change intended.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Link: https://patch.msgid.link/20260306232238.2039675-17-sean.wang@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>