usb: misc: usbio: Fix URB memory leak on submit failure

When usb_submit_urb() fails in usbio_probe(), the previously allocated
URB is never freed, causing a memory leak.

Fix this by jumping to err_free_urb label to properly release the URB
on the error path.

Fixes: 121a0f839dbb ("usb: misc: Add Intel USBIO bridge driver")
Cc: stable <[e-mail]>
Signed-off-by: Felix Gu <[e-mail]>
Reviewed-by: Oliver Neukum <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/usbio.c

···
 	usb_fill_bulk_urb(usbio->urb, udev, usbio->rx_pipe, usbio->rxbuf,
 			  usbio->rxbuf_len, usbio_bulk_recv, usbio);
 	ret = usb_submit_urb(usbio->urb, GFP_KERNEL);
-	if (ret)
-		return dev_err_probe(dev, ret, "Submitting usb urb\n");
+	if (ret) {
+		dev_err_probe(dev, ret, "Submitting usb urb\n");
+		goto err_free_urb;
+	}
 
 	mutex_lock(&usbio->ctrl_mutex);
 
···
 err_unlock:
 	mutex_unlock(&usbio->ctrl_mutex);
 	usb_kill_urb(usbio->urb);
+err_free_urb:
 	usb_free_urb(usbio->urb);
 
 	return ret;