meta-arm walnascar release

meta-arm has released the walnascar support branch.  The branch was
forked on 16 May 2025 from the master branch and was tagged as "5.2".  The
tag is GPG signed and my public key can be provided if someone wants to
use it to verify.  Per the previous public discussion on this list,
walnascar will only be taking bug fixes and be passively maintained
(with scarthgap being the actively supported LTS).

Per an external request, we have duplicated all existing numbers only
tags (i.e., 5.2) with a yocto-x.y.z tag (i.e., yocto-5.2).

Thanks,
Jon