The attached patch series adds support for the pine64.org Pinebook
laptop (similar to the Pine64+ already in Guix).

Summary of changes:
- Update arm-trusted-firmware-pine64-plus to use upstream git repository
  and newer commit.
- Rename arm-trusted-firmware-pine64-plus to.
  arm-trusted-firmware-sun50i-a64 to be consistant with upstream.
- Add a make-u-boot-package-sunxi64 wrapper function based on the
  u-boot-pine64-plus target.
- Add support for u-boot-pinebook, with patches from the u-boot sunxi
  maintainer tree backported to 2018.11.

I wasn't sure weather some of these patches should be squashed together
or not (especially 1 and 2, maybe 3 and 4).

I used patches on top of the u-boot 2018.11 release rather than a git
repository with the patches included, as it took a much longer time to
download the git respository and more disk space, though I can take
another look at using the git repository if that is preferred.


live well,
  vagrant