UefiCpuPkg: Add GUID gEdkiiCpuFeaturesInitDoneGuid

UefiCpuPkg: Add GUID gEdkiiCpuFeaturesInitDoneGuid

GUID gEdkiiCpuFeaturesInitDoneGuid is used to indicate if CPU features have been
initialized.

On PEI phase, one gEdkiiCpuFeaturesInitDoneGuid PPI will be installed after CPU
features initialized.
On DXE phase, one gEdkiiCpuFeaturesInitDoneGuid Protocol will be installed after
CPU features initialized.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>