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>