arm64: dts: mt8192: Add dpi node

Add dpi node for mt8192 SoC.

Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220318144534.17996-18-allen-kh.cheng@mediatek.com


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