clk/soc: mediatek: mt6779: Bind clock driver from platform device

The mmsys driver is now the top level entry point for the multimedia
system (mmsys), we bind the clock driver by creating a platform device.
We also bind the MediaTek DRM driver which is not yet implement and
therefor will errror out for now.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20200518113156.25009-3-matthias.bgg@kernel.org


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