MdePkg: Remove Itanium leftover data structure (RH only)

Pawel Polawskirequested to merge
elkoniu/edk2-centos:c9s-1024vCPU into c9s

Merge Request Required Information

Summary of Changes

Removal of Itanium CPU data structure (deprecated) resulting in lifting 1024 vCPU limitation to around 8k vCPU. This is downstream version only as upstream review is still ongoing: https://edk2.groups.io/g/devel/topic/95384808#96834

Approved Bugzilla Ticket

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1983086

Merge request reports