dt-bindings: display: convert innolux,p120zdg-bf1 to DT Schema

v3:
  - Fix stray spaces

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Sandeep Panda <spanda@codeaurora.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408195109.32692-12-sam@ravnborg.org