MdeModulePkg/PiSmmCore: Remove SMM Perf entry

The perf measurement entry in SmmEntryPoint function
doesn't have significant meaning. So remove it now.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdeModulePkg/Core/PiSmmCore/PiSmmCore.c

@@ -644,8 +644,6 @@ SmmEntryPoint (
   VOID                        *CommunicationBuffer;
   UINTN                       BufferSize;
 
-  PERF_INMODULE_BEGIN ("SMM");
-
   //
   // Update SMST with contents of the SmmEntryContext structure
   //
@@ -738,8 +736,6 @@ SmmEntryPoint (
     //
     gSmmCorePrivate->InSmm = FALSE;
   }
-
-  PERF_INMODULE_END ("SMM");
 }
 
 /**