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>