wl12xx: check if elp wakeup failed

Check the return call from wl12xx_ps_elp_wakeup() and bail out if it
fails. This shouldn't happen, but if does there's a fundamental low
level issue.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Reviewed-by: Vidhya Govindan <vidhya.govindan@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/wl12xx/debugfs.c b/drivers/net/wireless/wl12xx/debugfs.c
index 3cc5460..94ad994 100644
--- a/drivers/net/wireless/wl12xx/debugfs.c
+++ b/drivers/net/wireless/wl12xx/debugfs.c
@@ -95,9 +95,13 @@
 
 static void wl12xx_debugfs_update_stats(struct wl12xx *wl)
 {
+	int ret;
+
 	mutex_lock(&wl->mutex);
 
-	wl12xx_ps_elp_wakeup(wl);
+	ret = wl12xx_ps_elp_wakeup(wl);
+	if (ret < 0)
+		goto out;
 
 	if (wl->state == WL12XX_STATE_ON &&
 	    time_after(jiffies, wl->stats.fw_stats_update +
@@ -108,6 +112,7 @@
 
 	wl12xx_ps_elp_sleep(wl);
 
+out:
 	mutex_unlock(&wl->mutex);
 }