rsi: Use module_usb_driver

module_usb_driver eliminates the boilerplate and makes the code simpler,
in addition to the fact currently rsi_module_init() ignores usb_deregister() error.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rsi/rsi_91x_usb.c

@@ -550,33 +550,7 @@ static struct usb_driver rsi_driver = {
 #endif
 };
 
-/**
- * rsi_module_init() - This function registers the client driver.
- * @void: Void.
- *
- * Return: 0 on success.
- */
-static int rsi_module_init(void)
-{
-	usb_register(&rsi_driver);
-	rsi_dbg(INIT_ZONE, "%s: Registering driver\n", __func__);
-	return 0;
-}
-
-/**
- * rsi_module_exit() - This function unregisters the client driver.
- * @void: Void.
- *
- * Return: None.
- */
-static void rsi_module_exit(void)
-{
-	usb_deregister(&rsi_driver);
-	rsi_dbg(INFO_ZONE, "%s: Unregistering driver\n", __func__);
-}
-
-module_init(rsi_module_init);
-module_exit(rsi_module_exit);
+module_usb_driver(rsi_driver);
 
 MODULE_AUTHOR("Redpine Signals Inc");
 MODULE_DESCRIPTION("Common USB layer for RSI drivers");