ath9k: Store the correct max TX power level

This patch fixes a bug where the max power level
was being calculated incorrectly.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/eeprom.c b/drivers/net/wireless/ath9k/eeprom.c
index b55e992..34e9d81 100644
--- a/drivers/net/wireless/ath9k/eeprom.c
+++ b/drivers/net/wireless/ath9k/eeprom.c
@@ -2615,6 +2615,21 @@
 	else
 		ah->regulatory.max_power_level = ratesArray[i];
 
+	switch(ar5416_get_ntxchains(ah->txchainmask)) {
+	case 1:
+		break;
+	case 2:
+		ah->regulatory.max_power_level += INCREASE_MAXPOW_BY_TWO_CHAIN;
+		break;
+	case 3:
+		ah->regulatory.max_power_level += INCREASE_MAXPOW_BY_THREE_CHAIN;
+		break;
+	default:
+		DPRINTF(ah->ah_sc, ATH_DBG_EEPROM,
+			"Invalid chainmask configuration\n");
+		break;
+	}
+
 	return 0;
 }