MdeModulePkg/Core/PiSmmCore: rebase to ARRAY_SIZE()

Cc: Feng Tian <feng.tian@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Feng Tian <feng.tian@Intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

MdeModulePkg/Core/PiSmmCore/Pool.c

@@ -42,7 +42,7 @@ SmmInitializeMemoryServices (
   //
   // Initialize Pool list
   //
-  for (Index = sizeof (mSmmPoolLists) / sizeof (*mSmmPoolLists); Index > 0;) {
+  for (Index = ARRAY_SIZE (mSmmPoolLists); Index > 0;) {
     InitializeListHead (&mSmmPoolLists[--Index]);
   }
   CurrentSmramRangesIndex = 0;