dt-bindings: display: panel: Add binding document for Elida KD35T133

The KD35T133 is a 3.5" 320x480 DSI display used in the RK3326-based
Odroid Go Advance handheld device.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200229151506.750242-2-heiko@sntech.de