iio: adc: ab8500-gpadc: 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/20211008092858.495-1-caihuoqing@baidu.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ab8500-gpadc.c

@@ -1103,17 +1103,15 @@ static int ab8500_gpadc_probe(struct platform_device *pdev)
 		return ret;
 
 	gpadc->irq_sw = platform_get_irq_byname(pdev, "SW_CONV_END");
-	if (gpadc->irq_sw < 0) {
-		dev_err(dev, "failed to get platform sw_conv_end irq\n");
-		return gpadc->irq_sw;
-	}
+	if (gpadc->irq_sw < 0)
+		return dev_err_probe(dev, gpadc->irq_sw,
+				     "failed to get platform sw_conv_end irq\n");
 
 	if (is_ab8500(gpadc->ab8500)) {
 		gpadc->irq_hw = platform_get_irq_byname(pdev, "HW_CONV_END");
-		if (gpadc->irq_hw < 0) {
-			dev_err(dev, "failed to get platform hw_conv_end irq\n");
-			return gpadc->irq_hw;
-		}
+		if (gpadc->irq_hw < 0)
+			return dev_err_probe(dev, gpadc->irq_hw,
+					     "failed to get platform hw_conv_end irq\n");
 	} else {
 		gpadc->irq_hw = 0;
 	}
@@ -1146,11 +1144,9 @@ static int ab8500_gpadc_probe(struct platform_device *pdev)
 
 	/* The VTVout LDO used to power the AB8500 GPADC */
 	gpadc->vddadc = devm_regulator_get(dev, "vddadc");
-	if (IS_ERR(gpadc->vddadc)) {
-		ret = PTR_ERR(gpadc->vddadc);
-		dev_err(dev, "failed to get vddadc\n");
-		return ret;
-	}
+	if (IS_ERR(gpadc->vddadc))
+		return dev_err_probe(dev, PTR_ERR(gpadc->vddadc),
+				     "failed to get vddadc\n");
 
 	ret = regulator_enable(gpadc->vddadc);
 	if (ret) {