staging: comedi: amplc_pc263: remove subdevice pointer math

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

drivers/staging/comedi/drivers/amplc_pc263.c

@@ -225,7 +225,7 @@ static int pc263_common_attach(struct comedi_device *dev, unsigned long iobase)
 	if (ret)
 		return ret;
 
-	s = dev->subdevices + 0;
+	s = &dev->subdevices[0];
 	/* digital output subdevice */
 	s->type = COMEDI_SUBD_DO;
 	s->subdev_flags = SDF_READABLE | SDF_WRITABLE;