drm/mediatek: Refine device table of OVL adaptor

- Adjust indentation to align with other files
- Sort device table in alphabetical order
- Add sentinel to device table

Reviewed-by: CK Hu <ck.hu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231214055847.4936-18-shawn.sung@mediatek.com/


Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>