Enable cross-building nvk and panvk for Android to make it easier to spot build regressions. NOTE: nvk is built only for x86_64, and panvk is built only for aarch64. Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com> Reviewed-by: Valentine Burley <valentine.burley@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36710>