UefiCpuPkg: Uses gMmst in MmSaveStateLib

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4182

Use gMmst instead of gSmst.
Replace SmmServicesTableLib with MmServicesTableLib.

Cc: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Abner Chang <abner.chang@amd.com>
Signed-off-by: Abdul Lateef Attar <AbdulLateef.Attar@amd.com>

UefiCpuPkg/Library/MmSaveStateLib/IntelMmSaveStateLib.inf

@@ -31,4 +31,4 @@
   BaseLib
   BaseMemoryLib
   DebugLib
-  SmmServicesTableLib
+  MmServicesTableLib