ath9k: remove useless variable assignment in ath_mci_intr()

Value assigned to variable offset at line 551 is overwritten at line 562,
before it can be used. This makes such variable assignment useless.

Addresses-Coverity-ID: 1226941
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

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

@@ -548,7 +548,7 @@ void ath_mci_intr(struct ath_softc *sc)
 
 	if (mci_int_rxmsg & AR_MCI_INTERRUPT_RX_MSG_SCHD_INFO) {
 		mci_int_rxmsg &= ~AR_MCI_INTERRUPT_RX_MSG_SCHD_INFO;
-		offset = ar9003_mci_state(ah, MCI_STATE_LAST_SCHD_MSG_OFFSET);
+		ar9003_mci_state(ah, MCI_STATE_LAST_SCHD_MSG_OFFSET);
 	}
 
 	if (mci_int_rxmsg & AR_MCI_INTERRUPT_RX_MSG_GPM) {