Hi there,
The skiboot project (generally) doesn‘t take contributions via github pull requests. Contributions should sent to the skiboot mailing list using the git-format-patch and git-send-email tools. If you’re unfamiliar with these tools, there's a guide here:
https://www.freedesktop.org/wiki/Software/PulseAudio/HowToUseGitSendEmail/
The list address is:
skiboot@lists.ozlabs.org
Posting to the list does not require subscribing to the list. Posts from a non-subscribers are moderated to cut down on spam, but anyone posting genuine contributions will be whitelisted.
See https://open-power.github.io/skiboot/ for more details.