OvmfPkg: S3 Suspend: save ACPI context

OvmfPkg: S3 Suspend: save ACPI context

"OvmfPkg/AcpiS3SaveDxe/AcpiS3SaveDxe.inf" (originally:
"IntelFrameworkModulePkg/Universal/Acpi/AcpiS3SaveDxe/AcpiS3SaveDxe.inf")
produces the EFI_ACPI_S3_SAVE_PROTOCOL.

When found, this protocol is automatically invoked by
BdsLibBootViaBootOption(), in file
"IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c", right before
booting a boot option, to save ACPI S3 context.

At that point during BDS, our AcpiPlatformDxe driver will have installed
the FACS table (which AcpiS3SaveDxe has a use-time dependency upon).

With regard to dependencies: AcpiS3SaveDxe implements
EFI_ACPI_S3_SAVE_PROTOCOL by relying on LockBoxLib.

  BdsLibBootViaBootOption()
    EFI_ACPI_S3_SAVE_PROTOCOL [AcpiS3SaveDxe]
      LockBoxLib [OvmfPkg/Library/LockBoxLib]

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
[jordan.l.justen@intel.com: Remove EmuNvramLib]
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@15303 6f19259b-4bc3-4df7-8a09-765794883524