UefiCpuPkg: Add GenSmmPageTable() to create smm page table

This commit is code refinement to current smm pagetable generation
code. Add a new GenSmmPageTable() API to create smm page table
based on the PageTableMap() API in CpuPageTableLib. Caller only
needs to specify the paging mode and the PhysicalAddressBits to map.
This function can be used to create both IA32 pae paging and X64
5level, 4level paging.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>

UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h

@@ -555,6 +555,21 @@ Gen4GPageTable (
   IN      BOOLEAN  Is32BitPageTable
   );
 
+/**
+  Create page table based on input PagingMode and PhysicalAddressBits in smm.
+
+  @param[in]      PagingMode           The paging mode.
+  @param[in]      PhysicalAddressBits  The bits of physical address to map.
+
+  @retval         PageTable Address
+
+**/
+UINTN
+GenSmmPageTable (
+  IN PAGING_MODE  PagingMode,
+  IN UINT8        PhysicalAddressBits
+  );
+
 /**
   Initialize global data for MP synchronization.