Staging: west bridge, cyasgadget fix for usb_gadget_probe_driver

This patch fixes the west bridge cyasgadget driver in order to allow for
compilation against the linux-next tree. This changes
usb_gadget_register_driver to usb_gadget_probe_driver and updates this
function based on the new function definition (bind call).

Signed-off-by: David Cross <david.cross@cypress.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>