wl12xx: use module_platform_driver

Use a module_platform_driver declaration instead of replicating the
init and exit functions in the driver.

Based on the patch for wl18xx by Devendra Naga.
Signed-off-by: Luciano Coelho <luca@coelho.fi>

drivers/net/wireless/ti/wl12xx/main.c

@@ -1714,17 +1714,7 @@ static struct platform_driver wl12xx_driver = {
 	}
 };
 
-static int __init wl12xx_init(void)
-{
-	return platform_driver_register(&wl12xx_driver);
-}
-module_init(wl12xx_init);
-
-static void __exit wl12xx_exit(void)
-{
-	platform_driver_unregister(&wl12xx_driver);
-}
-module_exit(wl12xx_exit);
+module_platform_driver(wl12xx_driver);
 
 module_param_named(fref, fref_param, charp, 0);
 MODULE_PARM_DESC(fref, "FREF clock: 19.2, 26, 26x, 38.4, 38.4x, 52");