UefiCpuPkg/MpInitLib: Implementation of MpInitLibStartupThisAP()

v4:
  1. Simply the internal function StartupThisAPWorker()'s comment
     header due to it is duplicated with MpInitLibStartupThisAP().

v3:
  1. Use CamelCase for mStopCheckAllApsStatus and
     CheckAndUpdateApsStatus().

Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Giri P Mudusuru <giri.p.mudusuru@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Michael Kinney <michael.d.kinney@intel.com>

UefiCpuPkg/Library/MpInitLib/DxeMpLib.c

@@ -390,7 +390,25 @@ MpInitLibStartupThisAP (
   OUT BOOLEAN                   *Finished               OPTIONAL
   )
 {
-  return EFI_UNSUPPORTED;
+  EFI_STATUS              Status;
+
+  //
+  // temporarily stop checkAllApsStatus for avoid resource dead-lock.
+  //
+  mStopCheckAllApsStatus = TRUE;
+
+  Status = StartupThisAPWorker (
+             Procedure,
+             ProcessorNumber,
+             WaitEvent,
+             TimeoutInMicroseconds,
+             ProcedureArgument,
+             Finished
+             );
+
+  mStopCheckAllApsStatus = FALSE;
+
+  return Status;
 }
 
 /**