OvmfPkg/CpuS3DataDxe: do not allocate useless register tables

OvmfPkg/CpuS3DataDxe: do not allocate useless register tables

CpuS3DataDxe allocates the "RegisterTable" and "PreSmmInitRegisterTable"
arrays in ACPI_CPU_DATA just so every processor in the system can have its
own empty register table, matched by APIC ID. This has never been useful
in practice.

Given commit e992cc3f4859 ("UefiCpuPkg PiSmmCpuDxeSmm: Reduce SMRAM
consumption in CpuS3.c", 2021-01-11), simply leave both
"AcpiCpuData->RegisterTable" and "AcpiCpuData->PreSmmInitRegisterTable"
initialized to the zero address. This simplifies the driver, and saves
both normal RAM (boot services data type memory) and -- in PiSmmCpuDxeSmm
-- SMRAM.

(This simplification backs out a good chunk of commit 1158fc8e2c7b
("OvmfPkg/CpuS3DataDxe: enable S3 resume after CPU hotplug", 2020-03-04).
But CpuS3DataDxe still differs between UefiCpuPkg and OvmfPkg, due to the
latter supporting CPU hotplug; thus, we can't remove OvmfPkg/CpuS3DataDxe
altogether.)

Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3159
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Message-Id: <20210119155440.2262-5-lersek@redhat.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>