mt76: mt7915: fix txpower init for TSSI off chips

Fix incorrect txpower init value for TSSI off chips which causes
too small txpower.

Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -124,7 +124,7 @@ int mt7915_eeprom_get_target_power(struct mt7915_dev *dev,
 				   struct ieee80211_channel *chan,
 				   u8 chain_idx)
 {
-	int index;
+	int index, target_power;
 	bool tssi_on;
 
 	if (chain_idx > 3)
@@ -133,15 +133,22 @@ int mt7915_eeprom_get_target_power(struct mt7915_dev *dev,
 	tssi_on = mt7915_tssi_enabled(dev, chan->band);
 
 	if (chan->band == NL80211_BAND_2GHZ) {
-		index = MT_EE_TX0_POWER_2G + chain_idx * 3 + !tssi_on;
+		index = MT_EE_TX0_POWER_2G + chain_idx * 3;
+		target_power = mt7915_eeprom_read(dev, index);
+
+		if (!tssi_on)
+			target_power += mt7915_eeprom_read(dev, index + 1);
 	} else {
-		int group = tssi_on ?
-			    mt7915_get_channel_group(chan->hw_value) : 8;
+		int group = mt7915_get_channel_group(chan->hw_value);
+
+		index = MT_EE_TX0_POWER_5G + chain_idx * 12;
+		target_power = mt7915_eeprom_read(dev, index + group);
 
-		index = MT_EE_TX0_POWER_5G + chain_idx * 12 + group;
+		if (!tssi_on)
+			target_power += mt7915_eeprom_read(dev, index + 8);
 	}
 
-	return mt7915_eeprom_read(dev, index);
+	return target_power;
 }
 
 static const u8 sku_cck_delta_map[] = {