refactor to use &raw mut

[antonio-hickey]

Replacing all occurrences of addr_of_mut!(place) with &raw mut place.

This will allow us to reduce macro complexity, and improve consistency with existing reference syntax as &raw mut is similar to &mut making it fit more naturally with other existing code.

[y86-dev]

I expected the CI to fail and it didn't, turns out I had some wrong configurations there. I fixed it now, could you rebase on top of main?

Also, since I'm synchronizing the commit as-is into the linux repository, could you add a commit description similar to the one you had in the series on the rust-for-linux mailing list? Thanks!

[antonio-hickey]

GitHub closed the PR because I used it's native sync from upstream instead of just rebasing using git like I should've and had to do anyways haha.

[y86-dev]

The nightly-msrv check failed, we need #![feature(raw_ref_op)] in the examples and tests. This is a bit annoying, since users that rely on versions 1.81 and earlier also need to do that, so we have to document it in the README. Could you add that? Thanks!
The "proper" msrv of the crate is 1.82 (when with no default features), so it's fine for those (since raw_ref_op is stable after 1.82, right?).

[antonio-hickey]

Yea I can fix the examples/tests, and update the README to account for not being stable in the nightly-msrv.

Also yea raw_ref_op went stable in 1.82, so it's fine for 1.82+