dt-bindings: display: panel-dsi-cm: convert to YAML

Convert panel-dsi-cm bindings to YAML and add
missing properties while at it.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200716125733.83654-2-sebastian.reichel@collabora.com