mt76: mt7921: use mt76_hw instead of open coding it

use mt76_hw instead of open coding it
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7921/main.c

@@ -491,7 +491,7 @@ mt7921_sniffer_interface_iter(void *priv, u8 *mac, struct ieee80211_vif *vif)
 
 void mt7921_set_runtime_pm(struct mt7921_dev *dev)
 {
-	struct ieee80211_hw *hw = dev->mphy.hw;
+	struct ieee80211_hw *hw = mt76_hw(dev);
 	struct mt76_connac_pm *pm = &dev->pm;
 	bool monitor = !!(hw->conf.flags & IEEE80211_CONF_MONITOR);