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/otg/fsl_otg.c b/drivers/usb/otg/fsl_otg.c
index 0f420b2..2a52ff1 100644
--- a/drivers/usb/otg/fsl_otg.c
+++ b/drivers/usb/otg/fsl_otg.c
@@ -1151,18 +1151,7 @@
 	},
 };
 
-static int __init fsl_usb_otg_init(void)
-{
-	pr_info(DRIVER_INFO "\n");
-	return platform_driver_register(&fsl_otg_driver);
-}
-module_init(fsl_usb_otg_init);
-
-static void __exit fsl_usb_otg_exit(void)
-{
-	platform_driver_unregister(&fsl_otg_driver);
-}
-module_exit(fsl_usb_otg_exit);
+module_platform_driver(fsl_otg_driver);
 
 MODULE_DESCRIPTION(DRIVER_INFO);
 MODULE_AUTHOR(DRIVER_AUTHOR);