mtd: nand: 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.

Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> # atmel
Reviewed-by: Paul Cercueil <paul@crapouillou.net> # ingenic
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> # ingenic
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> # intel
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> # meson
Acked-by: Roger Quadros <rogerq@kernel.org> # omap_elm
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> # renesas
Reviewed-by: Heiko Stuebner <heiko@sntech.de> # rockchip
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sunxi
Acked-by: Thierry Reding <treding@nvidia.com> # tegra
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230411113816.3472237-1-u.kleine-koenig@pengutronix.de