feat: add support for rock 4c plus

[DamiaPoquet]

Pull Request

What? (description)

Introducing support for ROCK 4C+ board from Radxa.

Why? (reasoning)

It is a powerful arm64 board widely used in self-hosted environments.

Acceptance

Please use the following checklist:

• [x] you linked an issue (if applicable)
• [ ] you included tests (if applicable)
• [ ] you ran conformance (make conformance)
• [ ] you formatted your code (make fmt)
• [ ] you linted your code (make lint)
• [ ] you generated documentation (make docs)
• [ ] you ran unit-tests (make unit-tests)

See make help for a description of the available targets.

Dependencies

#8065 https://github.com/siderolabs/pkgs/pull/908