arm: dts: mediatek: Fix existing NAND controller node name

Change the existing node name in order to match NAND controller DT
bindings.

Signed-off-by: Xiangsheng Hou <xiangsheng.hou@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230201021500.26769-4-xiangsheng.hou@mediatek.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>