[RFC] drivers: gpio: PrimeCell PL061 in Rust

[RFC] drivers: gpio: PrimeCell PL061 in Rust

A port to Rust of the PrimeCell PL061 GPIO driver.

This module is a work in progress and will be sent for review later
on, as well as separately from the Rust support.

However, it is included to show how an actual working module
written in Rust may look like.

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>