UefiCpuPkg/PiSmmCpuDxeSmm: Always initialze PSD

UefiCpuPkg/PiSmmCpuDxeSmm: Always initialze PSD

The following commit moved the initialization of the
default PROCESSOR_SMM_DESCRIPTOR from MpService.c to
SmramSaveState.c and made this initialization
conditional on the value returned by the
SmmCpuFeaturesGetSmiHandlerSize() library function.

https://github.com/tianocore/edk2/commit/f12367a0b1de7838f1cb8e0839e168ed7b862333

This changed the behavior of the PiSmmCpuDxeSmm module.
The initialization of the PROCESSOR_SMM_DESCRIPTOR is
moved before the call to SmmCpuFeaturesGetSmiHandlerSize()
to preserve the previous behavior.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>