[WIP 1/3] rust: Introduce atomic module

[Andrew Lunn]

> +//! These primitives should have the same semantics as their C counterparts, for precise definitions
> +//! of the semantics, please refer to tools/memory-model. Note that Linux Kernel Memory
> +//! (Consistency) Model is the only model for Rust development in kernel right now, please avoid to
> +//! use Rust's own atomics.

Is it possible to somehow poison rusts own atomics?  I would not be
too surprised if somebody with good Rust knowledge but new to the
kernel tries using Rusts atomics. Either getting the compiler to fail
the build, or it throws an Opps on first invocation would be good.

    Andrew