UefiCpuPkg/MpInitLib: Add MpInitLibStartupAllCPUs API.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1973

Add new MpInitLibStartupAllCPUs API uses to start all processors
at the same time.

Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Chandana Kumar <chandana.c.kumar@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Regression-tested-by: Laszlo Ersek <lersek@redhat.com>

UefiCpuPkg/Library/MpInitLib/DxeMpLib.c

@@ -1,7 +1,7 @@
 /** @file
   MP initialize support functions for DXE phase.
 
-  Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2016 - 2019, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -568,9 +568,10 @@ MpInitLibStartupAllAPs (
   //
   mStopCheckAllApsStatus = TRUE;
 
-  Status = StartupAllAPsWorker (
+  Status = StartupAllCPUsWorker (
              Procedure,
              SingleThread,
+             TRUE,
              WaitEvent,
              TimeoutInMicroseconds,
              ProcedureArgument,