turnip: use ir3_compiler_destroy instead of ralloc_free

Fixes: c0f22c3d9406ef3 "freedreno/ir3: add ir3_compiler_destroy()"

Signed-off-by: Hyunjun Ko <zzoon@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6808>
(cherry picked from commit ec1464077bb0cfad1e0a5181a976fbb8ba8015a4)