ath9k: fix beacon restart on channel change

commit 1186488b upstream.

Restart the beacon timers only if the beacon
was already configured. Otherwise beacons timers
are restarted unnecessarily in unassociated state too.
Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

@@ -295,7 +295,8 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw,
 	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);
 	}