staging: comedi: mpc624: remove subdevice pointer math

Convert the comedi_subdevice access from pointer math to array
access.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/mpc624.c

@@ -353,7 +353,7 @@ static int mpc624_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	if (ret)
 		return ret;
 
-	s = dev->subdevices + 0;
+	s = &dev->subdevices[0];
 	s->type = COMEDI_SUBD_AI;
 	s->subdev_flags = SDF_READABLE | SDF_DIFF;
 	s->n_chan = 8;