staging: comedi: comedi_bond: change return value of bonding_attach()

`bonding_attach()` is the comedi "attach" handler for the driver.  Any
non-negative return value is treated as successful, but 0 is the
preferred return value on success.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/comedi_bond.c

@@ -336,7 +336,7 @@ static int bonding_attach(struct comedi_device *dev,
 		dev->driver->driver_name, dev->board_name,
 		devpriv->nchans, devpriv->ndevs);
 
-	return 1;
+	return 0;
 }
 
 static void bonding_detach(struct comedi_device *dev)