https://github.com/openhwgroup/linux is to be deleted

https://github.com/openhwgroup/linux is a fork from a certain hash of https://github.com/torvalds/linux that has never been modified, and there are no further plans to modify it.

Users could have a misleading sense that https://github.com/openhwgroup/linux is an endorsed version of Linux for OpenHW projects, which it is not. Linux for CVA6 is available from https://github.com/openhwgroup/cva6-sdk/ (Buildroot) and https://github.com/openhwgroup/meta-cva6-yocto.

Therefore there was a consensus in 2025-10-28 CVA6 meeting to delete this repository. @J-Mallet, could you record as a comment below the hash that was used to create https://github.com/openhwgroup/linux so that we can recreate it in the unlikely case where we would need to restore it? @MikeOpenHWGroup will then delete https://github.com/openhwgroup/linux.