mfd: input: iio: ti_am335x_adc: use one structure for ti_tscadc_dev

The mfd driver creates platform data for the child devices and it is the
ti_tscadc_dev struct. This struct is copied for the two devices.
The copy of the structure makes a common lock in this structure a little
less usefull. Therefore the platform data is not a pointer to the
structure and the same structure is used.
While doing the change I noticed that the suspend/resume code assumes
the wrong pointer for ti_tscadc_dev and this has been fixed as well.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

drivers/iio/adc/ti_am335x_adc.c

@@ -140,7 +140,7 @@ static int tiadc_probe(struct platform_device *pdev)
 {
 	struct iio_dev		*indio_dev;
 	struct tiadc_device	*adc_dev;
-	struct ti_tscadc_dev	*tscadc_dev = pdev->dev.platform_data;
+	struct ti_tscadc_dev	*tscadc_dev = ti_tscadc_dev_get(pdev);
 	struct mfd_tscadc_board	*pdata;
 	int			err;
 
@@ -205,9 +205,10 @@ static int tiadc_suspend(struct device *dev)
 {
 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
-	struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
+	struct ti_tscadc_dev *tscadc_dev;
 	unsigned int idle;
 
+	tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 	if (!device_may_wakeup(tscadc_dev->dev)) {
 		idle = tiadc_readl(adc_dev, REG_CTRL);
 		idle &= ~(CNTRLREG_TSCSSENB);