Merge patch series "CI: Set up for an arm64 runner"

Merge patch series "CI: Set up for an arm64 runner"

Tom Rini <trini@konsulko.com> says:

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.

Link: https://lore.kernel.org/r/20241127172247.1488685-1-trini@konsulko.com