Staging: line6: replacing -EINVAL with retval

drivers/staging/line6/midi.c:147 send_midi_async() info: why not
propagate 'retval' from usb_submit_urb() instead of (-22)?
Signed-off-by: NAshvini Varatharaj <ashvinivaratharaj@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/line6/midi.c

@@ -144,7 +144,7 @@ static int send_midi_async(struct usb_line6 *line6, unsigned char *data,
 	if (retval < 0) {
 		dev_err(line6->ifcdev, "usb_submit_urb failed\n");
 		usb_free_urb(urb);
-		return -EINVAL;
+		return retval;
 	}
 
 	++line6->line6midi->num_active_send_urbs;