[X86][AVX512VBMI] add encoding and intrinsics for Multishift

Differential Revision: http://reviews.llvm.org/D16399



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259363 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed