drm/mediatek: dpi: Add config for mt8192

Add dpi config setting and compatible for MT8192.

Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>