mt76: mt7915: fix DBDC default band selection on MT7915D

This code was accidentally dropped while adding 6 GHz support

Fixes: b4d093e3 ("mt76: mt7915: add 6 GHz support")
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -152,6 +152,8 @@ static void mt7915_eeprom_parse_band_config(struct mt7915_phy *phy)
 			phy->mt76->cap.has_2ghz = true;
 			return;
 		}
+	} else if (val == MT_EE_BAND_SEL_DEFAULT && dev->dbdc_support) {
+		val = phy->band_idx ? MT_EE_BAND_SEL_5GHZ : MT_EE_BAND_SEL_2GHZ;
 	}
 
 	switch (val) {