pinctrl: sprd-sc9860: Convert to platform remove callback returning void

pinctrl: sprd-sc9860: 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().

To convert the sprd-sc9860 driver, make sprd_pinctrl_remove()
return void (instead of zero) and use .remove_new as callback.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231009162510.335208-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>