UefiCpuPkg/RegisterCpuFeaturesLib: Support MpServices2 only case.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2883



MpServices Ppi can be replaced by MpServices2 Ppi and MpServices2
Ppi is mandatory for RegisterCpuFeaturesLib functionality,
basing on this we can drop MpServices Ppi usage from the library
and the constraint that both Ppis must be installed.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>