AMDGPU/GCN: Bring processors in sync with AMDGPUUsage

  - Add gfx704
    - Change bonaire to gfx704
  - Remove gfx804
  - Remove gfx901
  - Remove gfx903

Differential Revision: https://reviews.llvm.org/D40046


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320194 91177308-0d34-0410-b5e6-96231b3b80d8
48 files changed