iio: adc: envelope-detector: 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/20200829064726.26268-3-krzk@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/envelope-detector.c

@@ -348,11 +348,9 @@ static int envelope_detector_probe(struct platform_device *pdev)
 	indio_dev->num_channels = 1;
 
 	env->dac = devm_iio_channel_get(dev, "dac");
-	if (IS_ERR(env->dac)) {
-		if (PTR_ERR(env->dac) != -EPROBE_DEFER)
-			dev_err(dev, "failed to get dac input channel\n");
-		return PTR_ERR(env->dac);
-	}
+	if (IS_ERR(env->dac))
+		return dev_err_probe(dev, PTR_ERR(env->dac),
+				     "failed to get dac input channel\n");
 
 	env->comp_irq = platform_get_irq_byname(pdev, "comp");
 	if (env->comp_irq < 0)
@@ -360,11 +358,9 @@ static int envelope_detector_probe(struct platform_device *pdev)
 
 	ret = devm_request_irq(dev, env->comp_irq, envelope_detector_comp_isr,
 			       0, "envelope-detector", env);
-	if (ret) {
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "failed to request interrupt\n");
-		return ret;
-	}
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request interrupt\n");
+
 	env->comp_irq_trigger = irq_get_trigger_type(env->comp_irq);
 	if (env->comp_irq_trigger & IRQF_TRIGGER_RISING)
 		env->comp_irq_trigger_inv |= IRQF_TRIGGER_FALLING;