UefiCpuPkg/PiSmmCpuDxeSmm: Consume PcdAcpiS3Enable to control the code

UefiCpuPkg/PiSmmCpuDxeSmm: Consume PcdAcpiS3Enable to control the code

if PcdAcpiS3Enable is disabled, then skip S3 related logic.

Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>