UefiCpuPkg/PiSmmCpuDxeSmm: Check SMM Debug Agent support or not

This patch is to check SMM Debug Agent support or not before
InitializeDebugAgent.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zeng Star <star.zeng@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@Intel.com>

UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c

@@ -112,6 +112,11 @@ BOOLEAN  mSmmReadyToLock = FALSE;
 //
 BOOLEAN  mSmmCodeAccessCheckEnable = FALSE;
 
+//
+// Global used to cache SMM Debug Agent Supported ot not
+//
+BOOLEAN  mSmmDebugAgentSupport = FALSE;
+
 //
 // Global copy of the PcdPteMemoryEncryptionAddressOrMask
 //
@@ -897,7 +902,7 @@ PiCpuSmmEntry (
   //
   // Initialize Debug Agent to support source level debug in SMM code
   //
-  InitializeDebugAgent (DEBUG_AGENT_INIT_SMM, NULL, NULL);
+  InitializeDebugAgent (DEBUG_AGENT_INIT_SMM, &mSmmDebugAgentSupport, NULL);
 
   //
   // Report the start of CPU SMM initialization.