Staging/iio/adc/touchscreen/MXS: distinguish i.MX23's and i.MX28's LRADC

The LRADC units in i.MX23 and i.MX28 differ and we need to distinguish both
SoC variants in order to make the touchscreen work on i.MX23

Signed-off-by: Juergen Beisert <jbe@pengutronix.de>
Tested-by: Marek Vasut <marex@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
Tested-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

CC: linux-arm-kernel@lists.infradead.org
CC: linux-input@vger.kernel.org
CC: devel@driverdev.osuosl.org
CC: Fabio Estevam <fabio.estevam@freescale.com>
CC: Jonathan Cameron <jic23@cam.ac.uk>

drivers/staging/iio/adc/mxs-lradc.c

@@ -177,6 +177,8 @@ struct mxs_lradc {
 
 	struct input_dev	*ts_input;
 	struct work_struct	ts_work;
+
+	enum mxs_lradc_id	soc;
 };
 
 #define	LRADC_CTRL0				0x00
@@ -917,6 +919,7 @@ static int mxs_lradc_probe(struct platform_device *pdev)
 	}
 
 	lradc = iio_priv(iio);
+	lradc->soc = (enum mxs_lradc_id)of_id->data;
 
 	/* Grab the memory area */
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);