rust: print: Add support for calling a function exactly once

rust: print: Add support for calling a function exactly once

Add the Rust equivalent of the kernel's `DO_ONCE_LITE` macro. While it
would be possible to implement the feature entirely as a Rust macro,
the functionality that can be implemented as regular functions has
been extracted and implemented as the `OnceLite` struct for better
code maintainability.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20251117002452.4068692-2-fujita.tomonori@gmail.com
[ Added prefix to title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>