[PATCH v2 7/8] rust: drm: gem: Add GEM object abstraction

[Alyssa Rosenzweig]

To the best of my ability, this is

    Reviewed-by: Alyssa Rosenzweig <alyssa at rosenzweig.io>

although this is rather above my current Rust abilities.

> +    match T::open(unsafe { &*obj }, file) {
> +        Err(e) => e.to_errno(),
> +        Ok(()) => 0,
> +    }

incidentally this would be another candidate for the helper I alluded to
earlier...