[OA-syst-ref] Changes to Zephyr SDK to run Xilinx zcu102 QEMU images

Hello,

As I mentioned during last week's sync, I submitted changes to Zephyr SDK to update/extend its Xilinx QEMU coverage to allow to run end-to-end OpenAMP images (as produced by OE/PetaLinux). Associated instructions are at https://github.com/pfalcon/openamp-system-reference/wiki/RunningXilinxOEWith... .

The changes will go into the next Zephyr SDK release.