zink: delete query rather than allocating a new one

It seems I had some fat fingers when writing this function, and I
accidentally ended up allocating a new query and immediately trying to
delete an uninitialized pool instead of just deleting the pool of the
query that was passed.

CoverityID: 1455196
Reviewed-by: Dave Airlie <airlied@redhat.com>

src/gallium/drivers/zink/zink_query.c

@@ -80,7 +80,7 @@ zink_destroy_query(struct pipe_context *pctx,
                    struct pipe_query *q)
 {
    struct zink_screen *screen = zink_screen(pctx->screen);
-   struct zink_query *query = CALLOC_STRUCT(zink_query);
+   struct zink_query *query = (struct zink_query *)q;
 
    vkDestroyQueryPool(screen->dev, query->query_pool, NULL);
 }