ath9k: fix beacon restart on channel change

Restart the beacon timers only if the beacon
was already configured. Otherwise beacons timers
are restarted unnecessarily in unassociated state too.

Cc: stable@kernel.org
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 0f1b624..a818e4f 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -285,7 +285,8 @@
 	ath9k_hw_set_interrupts(ah, ah->imask);
 
 	if (!(sc->sc_flags & (SC_OP_OFFCHANNEL))) {
-		ath_beacon_config(sc, NULL);
+		if (sc->sc_flags & SC_OP_BEACONS)
+			ath_beacon_config(sc, NULL);
 		ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work, 0);
 		ath_start_ani(common);
 	}