QEMU: Add support of ARCv2 processors

QEMU port for ARCv2 is almost ready and we're working on
opening all our work for starters via Synopsys GitHub repo
https://github.com/foss-for-synopsys-dwc-arc-processors/qemu
and later as a part of upstream project.

For now we submit changes for Zephyr SDK in for of a huge
cumulative patch.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Author: abrodkin