drm/panel-edp: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code.  However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

panel_edp_remove() always returned zero, so convert it to return void
without any loss and then just drop the return from
panel_edp_platform_remove().
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530074216.2195962-1-u.kleine-koenig@pengutronix.de

drivers/gpu/drm/panel/panel-edp.c

@@ -903,7 +903,7 @@ static int panel_edp_probe(struct device *dev, const struct panel_desc *desc,
 	return err;
 }
 
-static int panel_edp_remove(struct device *dev)
+static void panel_edp_remove(struct device *dev)
 {
 	struct panel_edp *panel = dev_get_drvdata(dev);
 
@@ -918,8 +918,6 @@ static int panel_edp_remove(struct device *dev)
 
 	kfree(panel->edid);
 	panel->edid = NULL;
-
-	return 0;
 }
 
 static void panel_edp_shutdown(struct device *dev)
@@ -1934,9 +1932,9 @@ static int panel_edp_platform_probe(struct platform_device *pdev)
 	return panel_edp_probe(&pdev->dev, id->data, NULL);
 }
 
-static int panel_edp_platform_remove(struct platform_device *pdev)
+static void panel_edp_platform_remove(struct platform_device *pdev)
 {
-	return panel_edp_remove(&pdev->dev);
+	panel_edp_remove(&pdev->dev);
 }
 
 static void panel_edp_platform_shutdown(struct platform_device *pdev)
@@ -1957,7 +1955,7 @@ static struct platform_driver panel_edp_platform_driver = {
 		.pm = &panel_edp_pm_ops,
 	},
 	.probe = panel_edp_platform_probe,
-	.remove = panel_edp_platform_remove,
+	.remove_new = panel_edp_platform_remove,
 	.shutdown = panel_edp_platform_shutdown,
 };