can: flexcan: 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/20230512212725.143824-8-u.kleine-koenig@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan/flexcan-core.c

@@ -2218,7 +2218,7 @@ static int flexcan_probe(struct platform_device *pdev)
 	return err;
 }
 
-static int flexcan_remove(struct platform_device *pdev)
+static void flexcan_remove(struct platform_device *pdev)
 {
 	struct net_device *dev = platform_get_drvdata(pdev);
 
@@ -2227,8 +2227,6 @@ static int flexcan_remove(struct platform_device *pdev)
 	unregister_flexcandev(dev);
 	pm_runtime_disable(&pdev->dev);
 	free_candev(dev);
-
-	return 0;
 }
 
 static int __maybe_unused flexcan_suspend(struct device *device)
@@ -2379,7 +2377,7 @@ static struct platform_driver flexcan_driver = {
 		.of_match_table = flexcan_of_match,
 	},
 	.probe = flexcan_probe,
-	.remove = flexcan_remove,
+	.remove_new = flexcan_remove,
 	.id_table = flexcan_id_table,
 };