ath9k: Enable extended synch for AR9485 to fix L0s recovery issue

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@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 a59cfce..3e0c8a1 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -1179,6 +1179,9 @@
 
 	pm_qos_update_request(&sc->pm_qos_req, 55);
 
+	if (ah->caps.pcie_lcr_extsync_en && common->bus_ops->extn_synch_en)
+		common->bus_ops->extn_synch_en(common);
+
 mutex_unlock:
 	mutex_unlock(&sc->mutex);