The OpenMAX standard is long dead and even the Raspberry Pi OS no longer supports it. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4976>
It's both easier to use that way and we can also reuse it when building locally. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4281>