[clang][opencl][codegen] Remove the insertion of `correctly-rounded-divide-sqrt-fp-math` fn-attr.
- `-cl-fp32-correctly-rounded-divide-sqrt` is already handled in a per-instruction manner by annotating the accuracy required. There's no need to add that fn-attr. So far, there's no in-tree backend handling that attr and that OpenCL specific option. - In case that out-of-tree backends are broken, this change could be reverted if those backends could not be fixed.