arm64: dts: mt8183: Add the mmsys reset bit to reset the dsi0

Reset the DSI hardware is needed to prevent different settings between
the bootloader and the kernel.

While here, also remove the undocumented and also not used
'mediatek,syscon-dsi' property.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210930103105.v4.5.I933f1532d7a1b2910843a9644c86a7d94a4b44e1@changeid


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