OvmfPkg: Refine SmmAccess implementation

This patch refines the SmmAccess implementation:
1. SmramMap will be retrieved from the
gEfiSmmSmramMemoryGuid instead of original from
the TSEG Memory Base register.
2. Remove the gEfiAcpiVariableGuid creation, thus
the DESCRIPTOR_INDEX definition can be also cleaned.
3. The gEfiAcpiVariableGuid HOB is moved to the
OvmfPkg/Library/PlatformInitLib/PlatformInitLib.inf.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>

OvmfPkg/SmmAccess/SmramInternal.h

@@ -3,6 +3,7 @@
   Functions and types shared by the SMM accessor PEI and DXE modules.
 
   Copyright (C) 2015, Red Hat, Inc.
+  Copyright (c) 2024 Intel Corporation.
 
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
@@ -10,20 +11,8 @@
 
 #include <Pi/PiMultiPhase.h>
 
-//
-// We'll have two SMRAM ranges.
-//
-// The first is a tiny one that hosts an SMM_S3_RESUME_STATE object, to be
-// filled in by the CPU SMM driver during normal boot, for the PEI instance of
-// the LockBox library (which will rely on the object during S3 resume).
-//
-// The other SMRAM range is the main one, for the SMM core and the SMM drivers.
-//
-typedef enum {
-  DescIdxSmmS3ResumeState = 0,
-  DescIdxMain             = 1,
-  DescIdxCount            = 2
-} DESCRIPTOR_INDEX;
+#include <Guid/SmramMemoryReserve.h>
+#include <Library/HobLib.h>
 
 //
 // The value of PcdQ35TsegMbytes is saved into this variable at module startup.
@@ -97,8 +86,6 @@ SmramAccessLock (
 
 EFI_STATUS
 SmramAccessGetCapabilities (
-  IN BOOLEAN                   LockState,
-  IN BOOLEAN                   OpenState,
   IN OUT UINTN                 *SmramMapSize,
   IN OUT EFI_SMRAM_DESCRIPTOR  *SmramMap
   );