ath9k: Fix PS wrappers in ath9k_set_coverage_class

this callback is called during suspend/resume and also via iw command.
it configures parameters like sifs, slottime, acktimeout in
ath9k_hw_init_global_settings where few REG_READ, REG_RMW are also done
and hence the need for PS wrappers

Cc: stable@kernel.org
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -2283,7 +2283,11 @@ static void ath9k_set_coverage_class(struct ieee80211_hw *hw, u8 coverage_class)
 
 	mutex_lock(&sc->mutex);
 	ah->coverage_class = coverage_class;
+
+	ath9k_ps_wakeup(sc);
 	ath9k_hw_init_global_settings(ah);
+	ath9k_ps_restore(sc);
+
 	mutex_unlock(&sc->mutex);
 }