ath9k: remove variable which is set but never read

No functional changes - this only removes a variable which is set but
never read.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Reviewed-by: Julian Calaby <julian.calaby@gmail.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath9k/hw.c

@@ -474,15 +474,12 @@ static void ath9k_hw_init_defaults(struct ath_hw *ah)
 static int ath9k_hw_init_macaddr(struct ath_hw *ah)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
-	u32 sum;
 	int i;
 	u16 eeval;
 	static const u32 EEP_MAC[] = { EEP_MAC_LSW, EEP_MAC_MID, EEP_MAC_MSW };
 
-	sum = 0;
 	for (i = 0; i < 3; i++) {
 		eeval = ah->eep_ops->get_eeprom(ah, EEP_MAC[i]);
-		sum += eeval;
 		common->macaddr[2 * i] = eeval >> 8;
 		common->macaddr[2 * i + 1] = eeval & 0xff;
 	}