soc: mediatek: Add deprecated compatible to mmsys

For backward compatibility we add the deprecated compatible.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221111082912.14557-1-matthias.bgg@kernel.org


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