ath9k: serialize ath9k_hw_setpower calls

Because ath9k_setpower is called from various contexts, we have to
protect it against concurrent calls.

Changes-licensed-under: ISC
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -559,6 +559,7 @@ struct ath_softc {
 	spinlock_t sc_resetlock;
 	spinlock_t sc_serial_rw;
 	spinlock_t ani_lock;
+	spinlock_t sc_pm_lock;
 	struct mutex mutex;
 
 	u8 curbssid[ETH_ALEN];