usb: gadget: m66592-udc: should not call gadget driver's .unbind

It has already been covered by udc core
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/m66592-udc.c

@@ -1492,8 +1492,6 @@ static int m66592_udc_stop(struct usb_gadget *g,
 
 	m66592_bclr(m66592, M66592_VBSE | M66592_URST, M66592_INTENB0);
 
-	driver->unbind(&m66592->gadget);
-
 	init_controller(m66592);
 	disable_controller(m66592);