Platform/Sgi: Add ACPI tables for RD-Fremont platform

RD-Fremont is the next platform in the Arm's reference design platform
series. This platform includes 32 CPUs but the fixed virtual platform
(FVP) simulates 16 CPUs of the platform. There is one CPU per cluster in
the system and so the FVP simulates 16 clusters. In preparation for
adding support for this platform, add the initial set of ACPI tables and
reuse existing ACPI tables as applicable to boot a operating system on
this platform.

Signed-off-by: Prabin CA <prabin.ca@arm.com>