AMDGPU: Add VI i16 support

Patch By: Wei Ding

Differential Revision: https://reviews.llvm.org/D18049

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285939 91177308-0d34-0410-b5e6-96231b3b80d8
42 files changed