USB: serial: mos7840: fix misleading interrupt-URB comment

The interrupt URB is killed at final port close since commit
0de9a702 ("USB: overhaul of mos7840 driver").

Fixes: 0de9a702 ("USB: overhaul of mos7840 driver")
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/mos7840.c

@@ -1036,9 +1036,7 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
 				serial,
 				serial->port[0]->interrupt_in_urb->interval);
 
-			/* start interrupt read for mos7840               *
-			 * will continue as long as mos7840 is connected  */
-
+			/* start interrupt read for mos7840 */
 			response =
 			    usb_submit_urb(serial->port[0]->interrupt_in_urb,
 					   GFP_KERNEL);