Marvell/Armada7k8k: Add common ACPI tables

This patch adds ACPI tables and necessary headers,
which are common for Armada7k8k SoCs. Per-board
tables and wiring up of support will be done in
the follow-up commits.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>