usb_wwan: switch to ->[sg]et_serial()

Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/usb/serial/option.c

@@ -1962,7 +1962,8 @@ static struct usb_serial_driver option_1port_device = {
 	.chars_in_buffer   = usb_wwan_chars_in_buffer,
 	.tiocmget          = usb_wwan_tiocmget,
 	.tiocmset          = usb_wwan_tiocmset,
-	.ioctl             = usb_wwan_ioctl,
+	.get_serial        = usb_wwan_get_serial_info,
+	.set_serial        = usb_wwan_set_serial_info,
 	.attach            = option_attach,
 	.release           = option_release,
 	.port_probe        = usb_wwan_port_probe,