Nil UUID is a special case with all zeros value. This patch is to handle this case to avoid the invalid DUID. Cc: Naveen Santhapur <naveens@amiindia.co.in> Cc: Ye Ting <ting.ye@intel.com> Cc: Fu Siyuan <siyuan.fu@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com> Reviewed-by: Ye Ting <ting.ye@intel.com> Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>