usb: convert drivers/usb/* to use module_platform_driver()

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

Cc: Felipe Balbi <balbi@ti.com>
Cc: Li Yang <leoli@freescale.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index a552453..745a308 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -3469,18 +3469,7 @@
 	.resume		= s3c_hsotg_resume,
 };
 
-static int __init s3c_hsotg_modinit(void)
-{
-	return platform_driver_register(&s3c_hsotg_driver);
-}
-
-static void __exit s3c_hsotg_modexit(void)
-{
-	platform_driver_unregister(&s3c_hsotg_driver);
-}
-
-module_init(s3c_hsotg_modinit);
-module_exit(s3c_hsotg_modexit);
+module_platform_driver(s3c_hsotg_driver);
 
 MODULE_DESCRIPTION("Samsung S3C USB High-speed/OtG device");
 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");