UefiCpuPkg/CpuMpPei: Add GDT migration support (CVE-2019-11098)

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1614



Moves the GDT to permanent memory in a memory discovered
callback. This is done to ensure the GDT authenticated in
pre-memory is not fetched from outside a verified location
after the permanent memory transition.

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>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>