Those definitions are not needed by the drivers (client code), so
reduce the exposure. This will help when using both brw and elk in
Iris later.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27563>