dt-bindings: display: convert sharp,ls037v7dw01 to DT Schema

v2:
  - Add min/maxItems to mode-gpios (Rob)
  - Fix bug in description, mode is up to three gpios (Rob)

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408195109.32692-32-sam@ravnborg.org