MdePkg: Removed IPF related code

MdePkg: Removed IPF related code

A previous commit(3cb0a311cb7e747d7be5c5076d0fff76ad256d2b) didn't
clean all IPF contents. So this change removes the rest contents.
https://bugzilla.tianocore.org/show_bug.cgi?id=1560

v2: Withdraw the removal of Mps.h. It is written in Mps.h that
    MPS only was included to support Itanium-based platform power on.
    But we found MPS is not so relevant to Itanium architecture.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>