Input: misc - use macro module_platform_driver()

Commit 940ab88962bc1aff3273a8356d64577a6e386736 introduced a new macro to
save some platform_driver boilerplate code. Use it.

Signed-off-by: JJ Ding <dgdunix@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/misc/cobalt_btns.c b/drivers/input/misc/cobalt_btns.c
index fd8407a..53e43d2 100644
--- a/drivers/input/misc/cobalt_btns.c
+++ b/drivers/input/misc/cobalt_btns.c
@@ -163,16 +163,4 @@
 		.owner	= THIS_MODULE,
 	},
 };
-
-static int __init cobalt_buttons_init(void)
-{
-	return platform_driver_register(&cobalt_buttons_driver);
-}
-
-static void __exit cobalt_buttons_exit(void)
-{
-	platform_driver_unregister(&cobalt_buttons_driver);
-}
-
-module_init(cobalt_buttons_init);
-module_exit(cobalt_buttons_exit);
+module_platform_driver(cobalt_buttons_driver);