The default lib prefix is `lib`, so adding `lib` to the lib name just
results in `liblibbroadcom_v3d.a` for instance.
Those are internal, build-temporary static libraries that end up being
linked into the real user-visible libraries, so it doesn't really
matter, but we might as well just clean up their names anyway.
Reviewed-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Juan A. Suarez <jasuarez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18171>