OvmfPkg: remove PcdS3AcpiReservedMemoryBase, PcdS3AcpiReservedMemorySize

OvmfPkg: remove PcdS3AcpiReservedMemoryBase, PcdS3AcpiReservedMemorySize

No module in OvmfPkg uses these PCDs any longer.

The first PCD mentioned is declared by OvmfPkg, so we can remove even the
declaration.

The second PCD comes from IntelFrameworkModulePkg. The module that
consumes PcdS3AcpiReservedMemorySize is called
"IntelFrameworkModulePkg/Universal/Acpi/AcpiS3SaveDxe", and it is built
into OVMF. However, AcpiS3SaveDxe consumes the PCD only conditionally: it
depends on the feature PCD called PcdFrameworkCompatibilitySupport, which
we never enable in OVMF.

The 32KB gap that used to be the S3 permanent PEI memory is left unused in
MEMFD for now; it never hurts to have a few KB available there, for future
features.

Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>