platform: andes/ae350: Add AE350 domain support

Add domains_init platform hook for Andes AE350, users can add domain
description in device tree and select FDT domain support in Kconfig
to achieve system-level partitioning.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>