serial: sprd: 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() will be 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>
Acked-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lore.kernel.org/r/20231110152927.70601-41-u.kleine-koenig@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sprd_serial.c

@@ -1076,7 +1076,7 @@ static struct uart_driver sprd_uart_driver = {
 	.cons = SPRD_CONSOLE,
 };
 
-static int sprd_remove(struct platform_device *dev)
+static void sprd_remove(struct platform_device *dev)
 {
 	struct sprd_uart_port *sup = platform_get_drvdata(dev);
 
@@ -1089,8 +1089,6 @@ static int sprd_remove(struct platform_device *dev)
 
 	if (!sprd_ports_num)
 		uart_unregister_driver(&sprd_uart_driver);
-
-	return 0;
 }
 
 static bool sprd_uart_is_console(struct uart_port *uport)
@@ -1257,7 +1255,7 @@ MODULE_DEVICE_TABLE(of, serial_ids);
 
 static struct platform_driver sprd_platform_driver = {
 	.probe		= sprd_probe,
-	.remove		= sprd_remove,
+	.remove_new	= sprd_remove,
 	.driver		= {
 		.name	= "sprd_serial",
 		.of_match_table = serial_ids,