wifi: mt76: mt76x02: fix MT76x0 external LNA gain handling

On MT76x0, LNA gain should be applied for both external and internal LNA.
On MT76x2, LNA gain should be treated as 0 for external LNA.
Move the LNA type based logic to mt76x2 in order to fix mt76x0.

Fixes: 2daa675 ("mt76x0: unify lna_gain parsing")
Reported-by: Shiji Yang <yangshiji66@outlook.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230919194747.31647-1-nbd@nbd.name

Author: nbd168

drivers/net/wireless/mediatek/mt76/mt76x02_eeprom.c

@@ -131,15 +131,8 @@ u8 mt76x02_get_lna_gain(struct mt76x02_dev *dev,
 			s8 *lna_2g, s8 *lna_5g,
 			struct ieee80211_channel *chan)
 {
-	u16 val;
 	u8 lna;
 
-	val = mt76x02_eeprom_get(dev, MT_EE_NIC_CONF_1);
-	if (val & MT_EE_NIC_CONF_1_LNA_EXT_2G)
-		*lna_2g = 0;
-	if (val & MT_EE_NIC_CONF_1_LNA_EXT_5G)
-		memset(lna_5g, 0, sizeof(s8) * 3);
-
 	if (chan->band == NL80211_BAND_2GHZ)
 		lna = *lna_2g;
 	else if (chan->hw_value <= 64)

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

@@ -256,7 +256,8 @@ void mt76x2_read_rx_gain(struct mt76x02_dev *dev)
 	struct ieee80211_channel *chan = dev->mphy.chandef.chan;
 	int channel = chan->hw_value;
 	s8 lna_5g[3], lna_2g;
-	u8 lna;
+	bool use_lna;
+	u8 lna = 0;
 	u16 val;
 
 	if (chan->band == NL80211_BAND_2GHZ)
@@ -275,7 +276,15 @@ void mt76x2_read_rx_gain(struct mt76x02_dev *dev)
 	dev->cal.rx.mcu_gain |= (lna_5g[1] & 0xff) << 16;
 	dev->cal.rx.mcu_gain |= (lna_5g[2] & 0xff) << 24;
 
-	lna = mt76x02_get_lna_gain(dev, &lna_2g, lna_5g, chan);
+	val = mt76x02_eeprom_get(dev, MT_EE_NIC_CONF_1);
+	if (chan->band == NL80211_BAND_2GHZ)
+		use_lna = !(val & MT_EE_NIC_CONF_1_LNA_EXT_2G);
+	else
+		use_lna = !(val & MT_EE_NIC_CONF_1_LNA_EXT_5G);
+
+	if (use_lna)
+		lna = mt76x02_get_lna_gain(dev, &lna_2g, lna_5g, chan);
+
 	dev->cal.rx.lna_gain = mt76x02_sign_extend(lna, 8);
 }
 EXPORT_SYMBOL_GPL(mt76x2_read_rx_gain);