usb: gadget: gadgetfs: add reset API at usb_gadget_driver

Add reset API at usb_gadget_driver, it calls disconnect handler currently,
but may do different things in future.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/legacy/inode.c

@@ -1775,6 +1775,7 @@ static struct usb_gadget_driver gadgetfs_driver = {
 	.bind		= gadgetfs_bind,
 	.unbind		= gadgetfs_unbind,
 	.setup		= gadgetfs_setup,
+	.reset		= gadgetfs_disconnect,
 	.disconnect	= gadgetfs_disconnect,
 	.suspend	= gadgetfs_suspend,