spi: rpc-if: 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.

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/20230303172041.2103336-61-u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-rpc-if.c

@@ -173,15 +173,13 @@ static int rpcif_spi_probe(struct platform_device *pdev)
 	return error;
 }
 
-static int rpcif_spi_remove(struct platform_device *pdev)
+static void rpcif_spi_remove(struct platform_device *pdev)
 {
 	struct spi_controller *ctlr = platform_get_drvdata(pdev);
 	struct rpcif *rpc = spi_controller_get_devdata(ctlr);
 
 	spi_unregister_controller(ctlr);
 	pm_runtime_disable(rpc->dev);
-
-	return 0;
 }
 
 static int __maybe_unused rpcif_spi_suspend(struct device *dev)
@@ -202,7 +200,7 @@ static SIMPLE_DEV_PM_OPS(rpcif_spi_pm_ops, rpcif_spi_suspend, rpcif_spi_resume);
 
 static struct platform_driver rpcif_spi_driver = {
 	.probe	= rpcif_spi_probe,
-	.remove	= rpcif_spi_remove,
+	.remove_new = rpcif_spi_remove,
 	.driver = {
 		.name	= "rpc-if-spi",
 #ifdef CONFIG_PM_SLEEP