wifi: mt76: mt7925: update the power-saving flow

wifi: mt76: mt7925: update the power-saving flow

After joining MLO, ensure that all links are setup before
enabling power-saving.

Fixes: 86c051f2c418 ("wifi: mt76: mt7925: enabling MLO when the firmware supports it")
Cc: stable@vger.kernel.org
Co-developed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Tested-by: Caleb Jorden <cjorden@gmail.com>
Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Link: https://patch.msgid.link/20250305000851.493671-6-sean.wang@kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>