AMDGPU/R600: Convert buffer id to VTX_READ input

Use patterns instead of multiple instructions
Add buffer id to asm string

https://reviews.llvm.org/D22650

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278749 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed