PI specification Vol 4 - SMM does not have any limitation of BASE_4GB for SMM. So we should replace BASE_4GB check with MAX_ADDRESS check to make sure the SMM memory is accessible by SMM Core. Cc: Jeff Fan <jeff.fan@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jiewen Yao <jiewen.yao@intel.com> Reviewed-by: Jeff Fan <jeff.fan@intel.com> Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>