[v6 0/12] CI: Set up for an arm64 runner

[Tom Rini <trini@konsulko.com>]

Hey all,

This is picking up Simon's v5 of the above-named series and making a few
more changes so that the follow-up series I have leads to arm64 being
supported for almost all jobs. To quote Simon's cover letter:

All gitlab runners are currently amd64 machines. This series attempts to
create a docker image which can also support arm64 so that sandbox tests
can be run on it.

The TARGET_... environment variables for grub could perhaps be adjusted,
using the new variables, but I have not done that for now.

Adding to what Simon said, we now build grub for all architectures as
the reason to install it was to be able to use the binaries in QEMU.
That won't provide us with amd64 binaries on arm64 hosts so we can't use
that shortcut anymore.

Changes in v6:
- Re-introduce patches dropped in v4
- Add x86_64 toolchain
- Move to grub-2.12 and then build that (with -j$(nproc)) for all
  architectures

Changes in v5:
- Drop the comment in the gitlab file
- Add back a final missing sudo

Changes in v4:
- Leave the 'sudo' in

Changes in v3:
- Move ARGs to the top
- Revise documentation to explain a common error and building on arm64
- Use grub-efi and linux-image-generic for both archs
- Add patch to install toolchains on arm64 host
- Drop patches which remove grub and tracing for arm64

Changes in v2:
- Update docs also
- Add comments to the ARG variables
- Swap order so that amd64 is the exception

Link: https://lore.kernel.org/all/20241115134807.3068947-1-sjg@chromium.org/
-- 
Tom