Platform/Sgi: ACPI PPTT table for SGI575

Processor Properties Topology Table (PPTT) to describe the topological
structure of Processors as a hierarchical tree. PPTT also describes the
Cache private to each node in the hierarchy, and the vendor specific
information regarding the SoC package.

Change-Id: Id0f4a94247f6e228103785f09d8d7b264d399a98
Signed-off-by: Pranav Madhu <pranav.madhu@arm.com>