USB: serial: symbolserial.c: use module_usb_serial_driver

This converts the symbolserial.c driver to use the module_usb_serial_driver() call
instead of having to have a module_init/module_exit function, saving a lot
of duplicated code.

CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Johan Hovold <jhovold@gmail.com>
CC: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
CC: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/symbolserial.c

@@ -309,18 +309,8 @@ static struct usb_serial_driver * const serial_drivers[] = {
 	&symbol_device, NULL
 };
 
-static int __init symbol_init(void)
-{
-	return usb_serial_register_drivers(&symbol_driver, serial_drivers);
-}
-
-static void __exit symbol_exit(void)
-{
-	usb_serial_deregister_drivers(&symbol_driver, serial_drivers);
-}
+module_usb_serial_driver(symbol_driver, serial_drivers);
 
-module_init(symbol_init);
-module_exit(symbol_exit);
 MODULE_LICENSE("GPL");
 
 module_param(debug, bool, S_IRUGO | S_IWUSR);