Fix benchmark compilation failure: `cannot find attribute clap in this scope` (#14128)
[Two benchmark
jobs](https://github.com/astral-sh/uv/actions/runs/15732775460/job/44337710992?pr=14126)
were failing with `error: cannot find attribute clap in this scope`
based on #14120. This updates the recently added `#[clap(name = rocm...`
lines to use `cfg_attr(feature = "clap",`.