longanpi-4b: add support for Sipeed LonganPi 4B

[chainsx]

Description

longanpi-4b: add support for Sipeed LonganPi 4B. Add virt drivers for sun55iw3-syterkit.

How Has This Been Tested?

• [x] Successfully built.
• [x] System startup.

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] My changes generate no new warnings
• [x] Any dependent changes have been merged and published in downstream modules