AMDGPU/SI: Fix crash caused by r284267

Reviewers: arsenm, nhaehnle

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, tony-tye, llvm-commits

Differential Revision: https://reviews.llvm.org/D25782

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284875 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed