del_timer() got renamed to timer_delete() approximately in Linux 6.2
(similar for *_sync and likely others).
Keep the old functions as compat; unclear when we can gc them.
We should also re-define them with a linuxkpi_ prefix to avoid possible
conflicts in the future if we do a full pass over this at some point.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
X-MFC; preserve symbols, not inline