mt76: add missing lock configuring coverage class

Coverage class callback can potentially run in parallel with other
routines (e.g. mt7615_set_channel) that configures timing registers.
Run coverage class callback holding mt76 mutex

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7603/main.c

@@ -642,8 +642,10 @@ mt7603_set_coverage_class(struct ieee80211_hw *hw, s16 coverage_class)
 {
 	struct mt7603_dev *dev = hw->priv;
 
+	mutex_lock(&dev->mt76.mutex);
 	dev->coverage_class = max_t(s16, coverage_class, 0);
 	mt7603_mac_set_timing(dev);
+	mutex_unlock(&dev->mt76.mutex);
 }
 
 static void mt7603_tx(struct ieee80211_hw *hw,

drivers/net/wireless/mediatek/mt76/mt7615/main.c

@@ -735,9 +735,12 @@ static void
 mt7615_set_coverage_class(struct ieee80211_hw *hw, s16 coverage_class)
 {
 	struct mt7615_phy *phy = mt7615_hw_phy(hw);
+	struct mt7615_dev *dev = phy->dev;
 
+	mutex_lock(&dev->mt76.mutex);
 	phy->coverage_class = max_t(s16, coverage_class, 0);
 	mt7615_mac_set_timing(phy);
+	mutex_unlock(&dev->mt76.mutex);
 }
 
 static int

drivers/net/wireless/mediatek/mt76/mt7915/main.c

@@ -716,9 +716,12 @@ static void
 mt7915_set_coverage_class(struct ieee80211_hw *hw, s16 coverage_class)
 {
 	struct mt7915_phy *phy = mt7915_hw_phy(hw);
+	struct mt7915_dev *dev = phy->dev;
 
+	mutex_lock(&dev->mt76.mutex);
 	phy->coverage_class = max_t(s16, coverage_class, 0);
 	mt7915_mac_set_timing(phy);
+	mutex_unlock(&dev->mt76.mutex);
 }
 
 static int