[X86] Remove x86 InstrItinClass entries (PR37093)

This removes the last of the x86 schedule itineraries, I'm intending to cleanup the remaining uses of NoItinerary/OpndItins/etc. before resolving PR37093.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329967 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed