usb_gadget_unregister_driver
usb_gadget_unregister_driver(&driver->gadget_driver);
ret = usb_gadget_unregister_driver(&gi->composite.gadget_driver);
usb_gadget_unregister_driver(&dbgp_driver);
usb_gadget_unregister_driver (&gadgetfs_driver);
ret = usb_gadget_unregister_driver(&dev->driver);
EXPORT_SYMBOL_GPL(usb_gadget_unregister_driver);
int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);