UefiCpuPkg/SmmRelocationLib: Add SmmRelocationLib library instance

This patch just separates the smbase relocation logic from
PiSmmCpuDxeSmm driver, and moves to the SmmRelocationInit
interface. It maintains the original implementation of most
functions and leaves the definitions of global variables
intact. Further refinements to the code are planned for
subsequent patches.

Platform shall consume the interface for the smbase
relocation if need SMM support.

Note:
Before using SmmRelocationLib, the PiSmmCpuDxeSmm driver
allocates the SMRAM to be used for SMI handler and Save
state area of each processor from Smst->AllocatePages().
With SmmRelocationLib, the SMRAM allocation for SMI
handlers and Save state areas is moved to early PEI
phase (Smst->AllocatePages() service is not available).
So, the allocation is done by splitting the SMRAM out of
the SMRAM regions reported from gEfiSmmSMramMemoryGuid.

So, Platform must produce the gEfiSmmSMramMemoryGuid HOB
for SmmRelocationLib usage.

Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>

UefiCpuPkg/UefiCpuPkg.dsc

@@ -201,6 +201,7 @@
   UefiCpuPkg/Library/MmSaveStateLib/AmdMmSaveStateLib.inf
   UefiCpuPkg/Library/MmSaveStateLib/IntelMmSaveStateLib.inf
   UefiCpuPkg/Library/SmmCpuFeaturesLib/AmdSmmCpuFeaturesLib.inf
+  UefiCpuPkg/Library/SmmRelocationLib/SmmRelocationLib.inf
 
 [Components.X64]
   UefiCpuPkg/Library/CpuExceptionHandlerLib/UnitTest/DxeCpuExceptionHandlerLibUnitTest.inf