Add ASSERT to make sure 'ByteSeq' is not NULL before comsumed by CopyMem(). Cc: Eric Dong <eric.dong@intel.com> Cc: Feng Tian <feng.tian@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu <hao.a.wu@intel.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>