Clients are expecting the color info to be fully filled when the api
exists. Give proper defaults for the metadata to stay aligned with
legacy backends.
Fixes: 122fd46b15 ("Android15 support gralloc IMapper5")
Reviewed-by: Roman Stratiienko <r.stratiienko@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35613>