wlcore: unlock on error in wl1271_op_suspend()

We recently introduced a new error path which needs an unlock.

Fixes: 6d5a748d4836 ('wlcore: add ability to reduce FW interrupts during suspend')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ti/wlcore/main.c

@@ -1785,8 +1785,10 @@ static int wl1271_op_suspend(struct ieee80211_hw *hw,
 	mutex_lock(&wl->mutex);
 
 	ret = wl1271_ps_elp_wakeup(wl);
-	if (ret < 0)
+	if (ret < 0) {
+		mutex_unlock(&wl->mutex);
 		return ret;
+	}
 
 	wl->wow_enabled = true;
 	wl12xx_for_each_wlvif(wl, wlvif) {