mt76: mt7603: set 0 as min coverage_class value

Set 0 as minimum configurable value for coverage_class since mt76 does
not support dynack
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -642,7 +642,7 @@ mt7603_set_coverage_class(struct ieee80211_hw *hw, s16 coverage_class)
 {
 	struct mt7603_dev *dev = hw->priv;
 
-	dev->coverage_class = coverage_class;
+	dev->coverage_class = max_t(s16, coverage_class, 0);
 	mt7603_mac_set_timing(dev);
 }