UefiCpuPkg/CpuCommonFeaturesLib: Support X2APIC enable

Current X2APIC is enabled in MpInitLib (used by CpuMpPei and CpuDxe) to follow
SDM suggestion. That means we only enable X2APIC if we found there are any
initial CPU ID value >= 255.

This patch is to provide one chance for platform to enable X2APIC even there is
no any initial CPU ID value >= 255.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>

UefiCpuPkg/Library/CpuCommonFeaturesLib/CpuCommonFeatures.h

@@ -797,6 +797,21 @@ C1eInitialize (
   IN BOOLEAN                           State
   );
 
+/**
+  Prepares for the data used by CPU feature detection and initialization.
+
+  @param[in]  NumberOfProcessors  The number of CPUs in the platform.
+
+  @return  Pointer to a buffer of CPU related configuration data.
+
+  @note This service could be called by BSP only.
+**/
+VOID *
+EFIAPI
+X2ApicGetConfigData (
+  IN UINTN  NumberOfProcessors
+  );
+
 /**
   Detects if X2Apci feature supported on current processor.