ALSA: convert sound/* to use module_platform_driver()

This patch converts the drivers in sound/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/sparc/cs4231.c b/sound/sparc/cs4231.c
index 0e618f8..9aa90e0 100644
--- a/sound/sparc/cs4231.c
+++ b/sound/sparc/cs4231.c
@@ -2118,15 +2118,4 @@
 	.remove		= __devexit_p(cs4231_remove),
 };
 
-static int __init cs4231_init(void)
-{
-	return platform_driver_register(&cs4231_driver);
-}
-
-static void __exit cs4231_exit(void)
-{
-	platform_driver_unregister(&cs4231_driver);
-}
-
-module_init(cs4231_init);
-module_exit(cs4231_exit);
+module_platform_driver(cs4231_driver);