[X86][LWP] Add missing LWP itinerary class to lwpins instructions

It's on all other LWP instruction but I missed it from lwpins, despite similar scheduling behaviour. 

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318751 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed