rust: block: refactor to use `&raw mut`

Replace all occurrences (one) 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.

Suggested-by: Benno Lossin <benno.lossin@proton.me>
Link: https://github.com/Rust-for-Linux/linux/issues/1148


Signed-off-by: Antonio Hickey <contact@antoniohickey.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250320020740.1631171-17-contact@antoniohickey.com


[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>