ath9k_hw: fix device ID check for AR956x

Because of the missing return, the macVersion value was being
overwritten with an invalid register read

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -279,6 +279,7 @@ static void ath9k_hw_read_revisions(struct ath_hw *ah)
 		return;
 	case AR9300_DEVID_QCA956X:
 		ah->hw_version.macVersion = AR_SREV_VERSION_9561;
+		return;
 	}
 
 	val = REG_READ(ah, AR_SREV) & AR_SREV_ID;