iwlwifi: missing unlock on error path

We should unlock here instead of returning -EINVAL directly.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn.c

@@ -3009,14 +3009,17 @@ static int iwl_mac_offchannel_tx_cancel_wait(struct ieee80211_hw *hw)
 
 	mutex_lock(&priv->mutex);
 
-	if (!priv->_agn.offchan_tx_skb)
-		return -EINVAL;
+	if (!priv->_agn.offchan_tx_skb) {
+		ret = -EINVAL;
+		goto unlock;
+	}
 
 	priv->_agn.offchan_tx_skb = NULL;
 
 	ret = iwl_scan_cancel_timeout(priv, 200);
 	if (ret)
 		ret = -EIO;
+unlock:
 	mutex_unlock(&priv->mutex);
 
 	return ret;