UefiCpuPkg: Change complex DEBUG_CODE() to DEBUG_CODE_BEGIN/END()

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3767

Update use of DEBUG_CODE(Expression) if Expression is a complex code
block with if/while/for/case statements that use {}.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>

UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c

@@ -597,12 +597,12 @@ PiCpuSmmEntry (
   // If support CPU hot plug, PcdCpuSmmEnableBspElection should be set to TRUE.
   // A constant BSP index makes no sense because it may be hot removed.
   //
-  DEBUG_CODE (
+  DEBUG_CODE_BEGIN ();
     if (FeaturePcdGet (PcdCpuHotPlugSupport)) {
 
       ASSERT (FeaturePcdGet (PcdCpuSmmEnableBspElection));
     }
-  );
+  DEBUG_CODE_END ();
 
   //
   // Save the PcdCpuSmmCodeAccessCheckEnable value into a global variable.