UefiCpuPkg/RegisterCpuFeaturesLib: Start all processors simultaneously.

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

For semaphore type register, it required all processors to do the
task at the same time.
Current logic begins BSP's task after all APs have finished their tasks.
This will caused set semaphore task hang if semaphore has package
level type.
This patch use new EDKII_PEI_MP_SERVICES2_PPI to start all processors at
the same time to fix the potential hang issue.

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>

UefiCpuPkg/Library/RegisterCpuFeaturesLib/DxeRegisterCpuFeaturesLib.c

@@ -1,7 +1,7 @@
 /** @file
   CPU Register Table Library functions.
 
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2017 - 2019, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -116,7 +116,7 @@ GetProcessorInformation (
                                       to check whether procedure has done.
 **/
 VOID
-StartupAPsWorker (
+StartupAllAPsWorker (
   IN  EFI_AP_PROCEDURE                 Procedure,
   IN  EFI_EVENT                        MpEvent
   )
@@ -248,7 +248,7 @@ CpuFeaturesInitialize (
     //
     // Wakeup all APs for programming.
     //
-    StartupAPsWorker (SetProcessorRegister, MpEvent);
+    StartupAllAPsWorker (SetProcessorRegister, MpEvent);
   }
 
   //