Platform/Sgi: Macro definitions for ACPI CPPC

Add helper macros required for use with ACPI collaborative processor
performance control (CPPC). This patch adds macros for initializing ACPI
_CPC and _PSD control method. The CPC initializer macro initializes _CPC
control method with revision 3 as specified in Arm FFH specification
1.1. The CPC initilizer exposes the reference performance counter and
delivered perfrmance counter (AMU registers) as FFixedHW registers. The
initilizer also expose the fastchannel memories for performance level
set performance limit set protocols as desired performance register and
performance limited register respectively.

Signed-off-by: Pranav Madhu <pranav.madhu@arm.com>
Reviewed-by: Thomas Abraham <thomas.abraham@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>