staging: comedi: ni_670x: return '0' for successful attach

The comedi core expects a < 0 value during the attach to indicate
an error. The normal 'success' return for the kernel is '0' so use
that here.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_670x.c

@@ -295,7 +295,7 @@ static int ni_670x_attach(struct comedi_device *dev,
 	dev_info(dev->class_dev, "%s: %s attached\n",
 		dev->driver->driver_name, dev->board_name);
 
-	return 1;
+	return 0;
 }
 
 static void ni_670x_detach(struct comedi_device *dev)