R600: Remove orphaned declarations

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196633 91177308-0d34-0410-b5e6-96231b3b80d8
Add a RequireStructuredCFG Field to TargetMachine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196634 91177308-0d34-0410-b5e6-96231b3b80d8