iio: afe: iio-rescale: 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/20200829064726.26268-9-krzk@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/afe/iio-rescale.c

@@ -276,11 +276,9 @@ static int rescale_probe(struct platform_device *pdev)
 	int ret;
 
 	source = devm_iio_channel_get(dev, NULL);
-	if (IS_ERR(source)) {
-		if (PTR_ERR(source) != -EPROBE_DEFER)
-			dev_err(dev, "failed to get source channel\n");
-		return PTR_ERR(source);
-	}
+	if (IS_ERR(source))
+		return dev_err_probe(dev, PTR_ERR(source),
+				     "failed to get source channel\n");
 
 	sizeof_ext_info = iio_get_channel_ext_info_count(source);
 	if (sizeof_ext_info) {