UefiCpuPkg: Add definitions for EDKII microcode patch HOB

UefiCpuPkg: Add definitions for EDKII microcode patch HOB

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2430

This commit will add the definitions for EDKII microcode patch HOB.

The intention of adding this HOB is to provide a scheme to store the below
information:

A. The base address and size of the microcode patches that are being
   loaded (from flash) into memory;
B. The information of detected microcode patch for each processor within
   the system.

The producer of the HOB will be the UefiCpuPkg/MpInitLib (where the load,
detect and apply of the microcode happen). The consumer of the HOB can be
modules that want to detect/apply the microcode patch by themselves again
later during the boot flow.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Signed-off-by: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>