Input: mouse - 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/mouse/pxa930_trkball.c b/drivers/input/mouse/pxa930_trkball.c
index ee3b0ca..a9e4bfd 100644
--- a/drivers/input/mouse/pxa930_trkball.c
+++ b/drivers/input/mouse/pxa930_trkball.c
@@ -250,19 +250,7 @@
 	.probe		= pxa930_trkball_probe,
 	.remove		= __devexit_p(pxa930_trkball_remove),
 };
-
-static int __init pxa930_trkball_init(void)
-{
-	return platform_driver_register(&pxa930_trkball_driver);
-}
-
-static void __exit pxa930_trkball_exit(void)
-{
-	platform_driver_unregister(&pxa930_trkball_driver);
-}
-
-module_init(pxa930_trkball_init);
-module_exit(pxa930_trkball_exit);
+module_platform_driver(pxa930_trkball_driver);
 
 MODULE_AUTHOR("Yong Yao <yaoyong@marvell.com>");
 MODULE_DESCRIPTION("PXA930 Trackball Mouse Driver");