usb: serial: handle -ENODEV quietly in generic_submit_read_urb

If a USB serial device (e.g. /dev/ttyUSB0) with an active program is
unplugged, an -ENODEV (19) error will be produced after it gives up
trying to resubmit a read.

  usb_serial_generic_submit_read_urb - usb_submit_urb failed: -19

Add -ENODEV as one of the permanent errors along with -EPERM that
usb_serial_generic_submit_read_urb() handles quietly without an error.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/generic.c

@@ -286,7 +286,7 @@ static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 
 	res = usb_submit_urb(port->read_urbs[index], mem_flags);
 	if (res) {
-		if (res != -EPERM) {
+		if (res != -EPERM && res != -ENODEV) {
 			dev_err(&port->dev,
 					"%s - usb_submit_urb failed: %d\n",
 					__func__, res);