UefiCpuPkg: Update SEC_IDT_TABLE struct

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3957
The reserved IDT table size in SecCore is too small for X64. Changed the type
of IdtTable in SEC_IDT_TABLE from UINT64 to IA32_IDT_GATE_DESCRIPTOR to have
sufficient size reserved in IdtTable for X64. dff

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Ashraf Ali S <ashraf.ali.s@intel.com>
Cc: Debkumar De <debkumar.de@intel.com>
Cc: Harry Han <harry.han@intel.com>
Cc: Catharine West <catharine.west@intel.com>
Signed-off-by: Ted Kuo <ted.kuo@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>

UefiCpuPkg/SecCore/SecMain.c

@@ -211,6 +211,7 @@ SecStartup (
 
   IdtTableInStack.PeiService = 0;
   for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index++) {
+    ZeroMem ((VOID *)&IdtTableInStack.IdtTable[Index], sizeof (IA32_IDT_GATE_DESCRIPTOR));
     CopyMem ((VOID *)&IdtTableInStack.IdtTable[Index], (VOID *)&mIdtEntryTemplate, sizeof (UINT64));
   }