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().

Returning an error if unregister_restart_handler() failed has no effect
but triggering another error message. So converting this driver to
.remove_new() has no effect but to suppress the duplicated error message.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231104211501.3676352-30-u.kleine-koenig@pengutronix.deSigned-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>