st_pbo/compute: Use the correct structure type when allocating a specialized key

Use pbo_spec_async_data instead of pbo_async_data.

Cc: mesa-stable
Signed-off-by: Corentin Noël <corentin.noel@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28173>

src/mesa/state_tracker/st_pbo_compute.c

@@ -844,7 +844,7 @@ add_spec_data(struct pbo_async_data *async, struct pbo_data *pd)
    struct pbo_spec_async_data *spec;
    struct set_entry *entry = _mesa_set_search_or_add(&async->specialized, pd, &found);
    if (!found) {
-      spec = calloc(1, sizeof(struct pbo_async_data));
+      spec = calloc(1, sizeof(struct pbo_spec_async_data));
       util_queue_fence_init(&spec->fence);
       memcpy(spec->data, pd, sizeof(struct pbo_data));
       entry->key = spec;