zink: free push descriptor pools on deinit

these are owned by the context, so destroy them when the context
requests destruction

cc: mesa-stable

Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15173>

src/gallium/drivers/zink/zink_descriptors.c

@@ -1081,6 +1081,8 @@ zink_descriptor_pool_deinit(struct zink_context *ctx)
       /* do not free: programs own these pools */
       _mesa_hash_table_destroy(ctx->dd->descriptor_pools[i], NULL);
    }
+   descriptor_pool_free(zink_screen(ctx->base.screen), ctx->dd->push_pool[0]);
+   descriptor_pool_free(zink_screen(ctx->base.screen), ctx->dd->push_pool[1]);
 }
 
 static bool