USB: option: add missing usb_mark_last_busy

We should call usb_mark_last_busy in all input paths, including the
interrupt completion handler.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 2003a66..df91ea9 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -1904,6 +1904,7 @@
 
 	/* Resubmit urb so we continue receiving IRQ data */
 	if (status != -ESHUTDOWN && status != -ENOENT) {
+		usb_mark_last_busy(port->serial->dev);
 		err = usb_submit_urb(urb, GFP_ATOMIC);
 		if (err)
 			dev_dbg(dev, "%s: resubmit intr urb failed. (%d)\n",