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/host/oxu210hp-hcd.c b/drivers/usb/host/oxu210hp-hcd.c
index dcd8898..6f62de5 100644
--- a/drivers/usb/host/oxu210hp-hcd.c
+++ b/drivers/usb/host/oxu210hp-hcd.c
@@ -3951,24 +3951,7 @@
 	}
 };
 
-static int __init oxu_module_init(void)
-{
-	int retval = 0;
-
-	retval = platform_driver_register(&oxu_driver);
-	if (retval < 0)
-		return retval;
-
-	return retval;
-}
-
-static void __exit oxu_module_cleanup(void)
-{
-	platform_driver_unregister(&oxu_driver);
-}
-
-module_init(oxu_module_init);
-module_exit(oxu_module_cleanup);
+module_platform_driver(oxu_driver);
 
 MODULE_DESCRIPTION("Oxford OXU210HP HCD driver - ver. " DRIVER_VERSION);
 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");