drm/mediatek: gamma: Add support for MT8195

Now that this driver supports 12-bit LUTs, we can add support for the
DISP_GAMMA found on the MT8195 SoC: add its driver data and compatible.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231012095736.100784-12-angelogioacchino.delregno@collabora.com/


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