Bluetooth: btusb: fix memory leak

If btusb_mtk_submit_wmt_recv_urb returns error, wc should be freed and
then error should be returned to prevent memory leak.

Addresses-Coverity: ("Prevent memory leak")
Fixes: 4cbb375e997d ("Bluetooth: btusb: Fixed too many in-token issue for Mediatek Chip.")
Signed-off-by: Muhammad Usama Anjum <musamaanjum@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -3345,7 +3345,7 @@ static int btusb_mtk_hci_wmt_sync(struct hci_dev *hdev,
 	/* Submit control IN URB on demand to process the WMT event */
 	err = btusb_mtk_submit_wmt_recv_urb(hdev);
 	if (err < 0)
-		return err;
+		goto err_free_wc;
 
 	/* The vendor specific WMT commands are all answered by a vendor
 	 * specific event and will have the Command Status or Command