ac/llvm: Don't use getTriple() on LLVM21+

setTargetTriple() takes a Triple now.

Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33981>
1 file changed