usb: gadget/bcm63xx_udc: 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/20230517230239.187727-28-u.kleine-koenig@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/bcm63xx_udc.c

@@ -2354,7 +2354,7 @@ static int bcm63xx_udc_probe(struct platform_device *pdev)
  * bcm63xx_udc_remove - Remove the device from the system.
  * @pdev: Platform device struct from the bcm63xx BSP code.
  */
-static int bcm63xx_udc_remove(struct platform_device *pdev)
+static void bcm63xx_udc_remove(struct platform_device *pdev)
 {
 	struct bcm63xx_udc *udc = platform_get_drvdata(pdev);
 
@@ -2363,13 +2363,11 @@ static int bcm63xx_udc_remove(struct platform_device *pdev)
 	BUG_ON(udc->driver);
 
 	bcm63xx_uninit_udc_hw(udc);
-
-	return 0;
 }
 
 static struct platform_driver bcm63xx_udc_driver = {
 	.probe		= bcm63xx_udc_probe,
-	.remove		= bcm63xx_udc_remove,
+	.remove_new	= bcm63xx_udc_remove,
 	.driver		= {
 		.name	= DRV_MODULE_NAME,
 	},