iio: dac: dpot-dac: Simplify with dev_err_probe()

Common pattern of handling deferred probe can be simplified with
dev_err_probe().  Less code and also it prints the error value.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20200829064726.26268-12-krzk@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/dpot-dac.c

@@ -183,18 +183,14 @@ static int dpot_dac_probe(struct platform_device *pdev)
 	indio_dev->num_channels = 1;
 
 	dac->vref = devm_regulator_get(dev, "vref");
-	if (IS_ERR(dac->vref)) {
-		if (PTR_ERR(dac->vref) != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "failed to get vref regulator\n");
-		return PTR_ERR(dac->vref);
-	}
+	if (IS_ERR(dac->vref))
+		return dev_err_probe(&pdev->dev, PTR_ERR(dac->vref),
+				     "failed to get vref regulator\n");
 
 	dac->dpot = devm_iio_channel_get(dev, "dpot");
-	if (IS_ERR(dac->dpot)) {
-		if (PTR_ERR(dac->dpot) != -EPROBE_DEFER)
-			dev_err(dev, "failed to get dpot input channel\n");
-		return PTR_ERR(dac->dpot);
-	}
+	if (IS_ERR(dac->dpot))
+		return dev_err_probe(&pdev->dev, PTR_ERR(dac->dpot),
+				     "failed to get dpot input channel\n");
 
 	ret = iio_get_channel_type(dac->dpot, &type);
 	if (ret < 0)