AMDGPU: Use CopyToReg for interp intrinsic lowering

This doesn't use the default value, so doesn't benefit from the hack
to help optimize it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375450 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed