drm/panel: ej030na: 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.
And using dev_err_probe() can reduce code size, and the error value
gets printed.
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210916104225.11111-1-caihuoqing@baidu.com

drivers/gpu/drm/panel/panel-innolux-ej030na.c

@@ -198,16 +198,14 @@ static int ej030na_probe(struct spi_device *spi)
 		return -EINVAL;
 
 	priv->supply = devm_regulator_get(dev, "power");
-	if (IS_ERR(priv->supply)) {
-		dev_err(dev, "Failed to get power supply\n");
-		return PTR_ERR(priv->supply);
-	}
+	if (IS_ERR(priv->supply))
+		return dev_err_probe(dev, PTR_ERR(priv->supply),
+				     "Failed to get power supply\n");
 
 	priv->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
-	if (IS_ERR(priv->reset_gpio)) {
-		dev_err(dev, "Failed to get reset GPIO\n");
-		return PTR_ERR(priv->reset_gpio);
-	}
+	if (IS_ERR(priv->reset_gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->reset_gpio),
+				     "Failed to get reset GPIO\n");
 
 	drm_panel_init(&priv->panel, dev, &ej030na_funcs,
 		       DRM_MODE_CONNECTOR_DPI);