CpuLib.h exposes StandardSignatureIsAuthenticAMD() API and we require stub function in its BaseCpuLibNull library instance to avoid potential link issue. Cc: Michael D Kinney <michael.d.kinney@intel.com> Cc: Liming Gao <gaoliming@byosoft.com.cn> Cc: Zhiguang Liu <zhiguang.liu@intel.com> Signed-off-by: Qing Huang <qing.huang@intel.com> Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>