UefiCpuPkg/CpuDxe: clean up PAGE_TABLE_LIB_PAGING_CONTEXT usage.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1039

Current implementation not checks system mode before using
PAGE_TABLE_LIB_PAGING_CONTEXT.ContextData.X64 or
PAGE_TABLE_LIB_PAGING_CONTEXT.ContextData.Ia32. This patch check the
mode before using the correct one.

Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

UefiCpuPkg/CpuDxe/CpuPageTable.h

@@ -139,4 +139,19 @@ AllocatePageTableMemory (
   IN UINTN           Pages
   );
 
+/**
+  Get paging details.
+
+  @param  PagingContextData      The paging context.
+  @param  PageTableBase          Return PageTableBase field.
+  @param  Attributes             Return Attributes field.
+
+**/
+VOID
+GetPagingDetails (
+  IN  PAGE_TABLE_LIB_PAGING_CONTEXT_DATA *PagingContextData,
+  OUT UINTN                              **PageTableBase     OPTIONAL,
+  OUT UINT32                             **Attributes        OPTIONAL
+  );
+
 #endif