ath9k: Fix build error in ath_reset_internal

drivers/net/wireless/ath/ath9k/main.c:299 ath_reset_internal()
error: we previously assumed 'hchan' could be null (see line 293)

Cc: Felix Fietkau <nbd@openwrt.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -314,11 +314,9 @@ int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan)
 	if (!ath_prepare_reset(sc))
 		fastcc = false;
 
-	if (hchan) {
-		spin_lock_bh(&sc->chan_lock);
-		sc->cur_chandef = sc->cur_chan->chandef;
-		spin_unlock_bh(&sc->chan_lock);
-	}
+	spin_lock_bh(&sc->chan_lock);
+	sc->cur_chandef = sc->cur_chan->chandef;
+	spin_unlock_bh(&sc->chan_lock);
 
 	ath_dbg(common, CONFIG, "Reset to %u MHz, HT40: %d fastcc: %d\n",
 		hchan->channel, IS_CHAN_HT40(hchan), fastcc);