iio: st_sensors: Make use of the helper function dev_err_probe()

When possible use dev_err_probe help to properly deal with the
PROBE_DEFER error, the benefit is that DEFER issue will be logged
in the devices_deferred debugfs file.
Using dev_err_probe() can reduce code size, and the error value
gets printed.
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20210928014055.1431-1-caihuoqing@baidu.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/common/st_sensors/st_sensors_core.c

@@ -228,10 +228,10 @@ int st_sensors_power_enable(struct iio_dev *indio_dev)
 
 	/* Regulators not mandatory, but if requested we should enable them. */
 	pdata->vdd = devm_regulator_get(parent, "vdd");
-	if (IS_ERR(pdata->vdd)) {
-		dev_err(&indio_dev->dev, "unable to get Vdd supply\n");
-		return PTR_ERR(pdata->vdd);
-	}
+	if (IS_ERR(pdata->vdd))
+		return dev_err_probe(&indio_dev->dev, PTR_ERR(pdata->vdd),
+				     "unable to get Vdd supply\n");
+
 	err = regulator_enable(pdata->vdd);
 	if (err != 0) {
 		dev_warn(&indio_dev->dev,
@@ -244,10 +244,10 @@ int st_sensors_power_enable(struct iio_dev *indio_dev)
 		return err;
 
 	pdata->vdd_io = devm_regulator_get(parent, "vddio");
-	if (IS_ERR(pdata->vdd_io)) {
-		dev_err(&indio_dev->dev, "unable to get Vdd_IO supply\n");
-		return PTR_ERR(pdata->vdd_io);
-	}
+	if (IS_ERR(pdata->vdd_io))
+		return dev_err_probe(&indio_dev->dev, PTR_ERR(pdata->vdd_io),
+				     "unable to get Vdd_IO supply\n");
+
 	err = regulator_enable(pdata->vdd_io);
 	if (err != 0) {
 		dev_warn(&indio_dev->dev,