staging: comedi: usbduxsigma: always clear the usb intfdata in (*detach)

Make sure the usb intfdata is always cleared when the device is
detached.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/usbduxsigma.c

@@ -1703,11 +1703,11 @@ static void usbduxsigma_detach(struct comedi_device *dev)
 	struct usb_interface *intf = comedi_to_usb_interface(dev);
 	struct usbduxsigma_private *devpriv = dev->private;
 
+	usb_set_intfdata(intf, NULL);
+
 	if (!devpriv)
 		return;
 
-	usb_set_intfdata(intf, NULL);
-
 	down(&devpriv->sem);
 
 	/* force unlink all urbs */