usb: gadget/snps_udc_plat: 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 ignored (apart from
emitting a warning) 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. Eventually after all drivers are converted, .remove_new() is
renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230517230239.187727-43-u.kleine-koenig@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/snps_udc_plat.c

@@ -225,7 +225,7 @@ static int udc_plat_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int udc_plat_remove(struct platform_device *pdev)
+static void udc_plat_remove(struct platform_device *pdev)
 {
 	struct udc *dev;
 
@@ -234,7 +234,7 @@ static int udc_plat_remove(struct platform_device *pdev)
 	usb_del_gadget_udc(&dev->gadget);
 	/* gadget driver must not be registered */
 	if (WARN_ON(dev->driver))
-		return 0;
+		return;
 
 	/* dma pool cleanup */
 	free_dma_pools(dev);
@@ -248,8 +248,6 @@ static int udc_plat_remove(struct platform_device *pdev)
 	extcon_unregister_notifier(dev->edev, EXTCON_USB, &dev->nb);
 
 	dev_info(&pdev->dev, "Synopsys UDC platform driver removed\n");
-
-	return 0;
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -315,7 +313,7 @@ MODULE_DEVICE_TABLE(of, of_udc_match);
 
 static struct platform_driver udc_plat_driver = {
 	.probe		= udc_plat_probe,
-	.remove		= udc_plat_remove,
+	.remove_new	= udc_plat_remove,
 	.driver		= {
 		.name	= "snps-udc-plat",
 		.of_match_table = of_match_ptr(of_udc_match),