usb: gadget: f_ncm: obtain cdev from function instead of driver_data

The 'driver_data' field in ep0 is never set to pointer to cdev, so we
have to obtain it from another source as in this context ep->driver_data
contains invalid data.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_ncm.c

@@ -586,7 +586,7 @@ static void ncm_ep0out_complete(struct usb_ep *ep, struct usb_request *req)
 	unsigned		in_size;
 	struct usb_function	*f = req->context;
 	struct f_ncm		*ncm = func_to_ncm(f);
-	struct usb_composite_dev *cdev = ep->driver_data;
+	struct usb_composite_dev *cdev = f->config->cdev;
 
 	req->context = NULL;
 	if (req->status || req->actual != req->length) {