mt76: mt76x2: fix 2.4 GHz channel gain settings

AGC register 35, 37 override for the low gain setting should only be done
on 5 GHz. Also, 2.4 GHz needs a different value for register 35
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x2/phy.c

@@ -285,6 +285,7 @@ void mt76x2_phy_update_channel_gain(struct mt76x02_dev *dev)
 {
 	u8 *gain = dev->cal.agc_gain_init;
 	u8 low_gain_delta, gain_delta;
+	u32 agc_35, agc_37;
 	bool gain_change;
 	int low_gain;
 	u32 val;
@@ -323,6 +324,16 @@ void mt76x2_phy_update_channel_gain(struct mt76x02_dev *dev)
 	else
 		low_gain_delta = 14;
 
+	agc_37 = 0x2121262c;
+	if (dev->mt76.chandef.chan->band == NL80211_BAND_2GHZ)
+		agc_35 = 0x11111516;
+	else if (low_gain == 2)
+		agc_35 = agc_37 = 0x08080808;
+	else if (dev->mt76.chandef.width == NL80211_CHAN_WIDTH_80)
+		agc_35 = 0x10101014;
+	else
+		agc_35 = 0x11111116;
+
 	if (low_gain == 2) {
 		mt76_wr(dev, MT_BBP(RXO, 18), 0xf000a990);
 		mt76_wr(dev, MT_BBP(AGC, 35), 0x08080808);
@@ -331,15 +342,13 @@ void mt76x2_phy_update_channel_gain(struct mt76x02_dev *dev)
 		dev->cal.agc_gain_adjust = 0;
 	} else {
 		mt76_wr(dev, MT_BBP(RXO, 18), 0xf000a991);
-		if (dev->mt76.chandef.width == NL80211_CHAN_WIDTH_80)
-			mt76_wr(dev, MT_BBP(AGC, 35), 0x10101014);
-		else
-			mt76_wr(dev, MT_BBP(AGC, 35), 0x11111116);
-		mt76_wr(dev, MT_BBP(AGC, 37), 0x2121262C);
 		gain_delta = 0;
 		dev->cal.agc_gain_adjust = low_gain_delta;
 	}
 
+	mt76_wr(dev, MT_BBP(AGC, 35), agc_35);
+	mt76_wr(dev, MT_BBP(AGC, 37), agc_37);
+
 	dev->cal.agc_gain_cur[0] = gain[0] - gain_delta;
 	dev->cal.agc_gain_cur[1] = gain[1] - gain_delta;
 	mt76x2_phy_set_gain_val(dev);