OvmfPkg: Add section of memory to use for PEI on S3 resume

This 32k section of RAM will be declared to the PEI Core on
S3 resume to allow memory allocations during S3 resume PEI.

If the boot mode is BOOT_ON_S3_RESUME, then we publish
the pre-reserved PcdS3AcpiReservedMemory range to PEI.

If the boot mode is not BOOT_ON_S3_RESUME, then we reserve
this range as ACPI NVS so the OS will not use it.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15294 6f19259b-4bc3-4df7-8a09-765794883524