dt-bindings: display: bridge: document Toshiba TC358768 cells and panel node

Inherit valid properties from the dsi-controller.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220207223911.97180-1-david@ixit.cz