MFC r349277:
LinuxKPI: Additions to rcu list.
- Add rcu list functions.
- Make rcu hlist's foreach macro use rcu calls instead of the non-rcu macro.
- Bump FreeBSD version so we have a checkpoint for the vboxvideo drm driver.
Reviewed by: hps
Approved by: imp (mentor), hps
MFC after: 1 week
Differential Revision: D20719