ath9k: Fix powersave locking

The 'ps_flags' is used/accessed in a variety of contexts
and requires proper locking. Use 'sc_pm_lock' appropriately.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index b54e159..fbdcc80 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -587,13 +587,13 @@
 
 	/* Process Beacon and CAB receive in PS state */
 	if (((sc->ps_flags & PS_WAIT_FOR_BEACON) || ath9k_check_auto_sleep(sc))
-	    && mybeacon)
+	    && mybeacon) {
 		ath_rx_ps_beacon(sc, skb);
-	else if ((sc->ps_flags & PS_WAIT_FOR_CAB) &&
-		 (ieee80211_is_data(hdr->frame_control) ||
-		  ieee80211_is_action(hdr->frame_control)) &&
-		 is_multicast_ether_addr(hdr->addr1) &&
-		 !ieee80211_has_moredata(hdr->frame_control)) {
+	} else if ((sc->ps_flags & PS_WAIT_FOR_CAB) &&
+		   (ieee80211_is_data(hdr->frame_control) ||
+		    ieee80211_is_action(hdr->frame_control)) &&
+		   is_multicast_ether_addr(hdr->addr1) &&
+		   !ieee80211_has_moredata(hdr->frame_control)) {
 		/*
 		 * No more broadcast/multicast frames to be received at this
 		 * point.
@@ -1229,7 +1229,6 @@
 			skb_trim(skb, skb->len - 8);
 
 		spin_lock_irqsave(&sc->sc_pm_lock, flags);
-
 		if ((sc->ps_flags & (PS_WAIT_FOR_BEACON |
 				     PS_WAIT_FOR_CAB |
 				     PS_WAIT_FOR_PSPOLL_DATA)) ||