CpuDxe entry point () only register exception handlers unassigned before.

Signed-off-by: vanjeff
Reviewed-by: rsun3

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11699 6f19259b-4bc3-4df7-8a09-765794883524

UefiCpuPkg/CpuDxe/CpuDxe.c

@@ -1141,7 +1141,7 @@ InitInterruptDescriptorTable (
   //
   // Initialize Exception Handlers
   //
-  for (Index = 0; Index < 32; Index++) {
+  for (Index = OldIdtSize; Index < 32; Index++) {
     Status = CpuRegisterInterruptHandler (&gCpu, Index, CommonExceptionHandler);
     ASSERT_EFI_ERROR (Status);
   }