Revert "AMDGPU: Add core backend files for R600/SI codegen v6"

This reverts commit 4ea70107c5e51230e9e60f0bf58a0f74aa4885ea.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160303 91177308-0d34-0410-b5e6-96231b3b80d8
114 files changed