Allow disabling hardware-accelerated KTLS receive for mlx5 and disable by default
It would be good to have this disabled by default in FreeBSD 14.
There is currently a deadlock described in: If removing a node of type FS_TYPE_FLOW_DEST we lock the flow group too late. This can lead to a deadlock and conflict with fs_add_dst_fg().
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=274715