AMDGPU: Remove legacy rsq.clamped intrinsic

Mesa still has a use of llvm.AMDGPU.rsq.f64 remaining.

Also fix mismatch with non-IEEE rsq selecting to IEEE rsq.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275617 91177308-0d34-0410-b5e6-96231b3b80d8
12 files changed