Add device tree overlay for Coral Boards, compile.

* Adds device tree overlay (compiled and source) for both platforms.
* RPi is expected to not need this (included on HAT EEPROM).
* Coral boards can add the dtbo to their overlays.txt to load on boot.

Change-Id: Ibc68008b24537205182db62aa40bdd6e335a6564
5 files changed