UefiCpuLib: Remove UefiCpuLib.

Because UefiCpuPkg/UefiCpuLib is merged to MdePkg/CpuLib and all modules
are updated to not depend on this library, remove it completely.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Signed-off-by: Yu Pu <yu.pu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>