panic: spin lock nv0 not in order list

[Danny Braniss]

> > with a fairly resent current im now getting:
> > ...
> > nv0: <NVIDIA nForce MCP2 Networking Adapter> port 0xd400-0xd407 mem=20
> > 0xdd087000-0xdd087fff irq 11 at device 4.0 on pci0
> > panic: spin lock nv0 not in order list
> > at line 1207 in file /r+d/5.2/src/sys/kern/subr_witness.c
> >=20
> So remove the debug.witness_skipspin=3D"0" line from /boot/loader.conf
> or the ``options WITNESS_SKIPSPIN'' from your kernel, or submit the
> trivial patch for subr_witness.c.  ;)

love to, but all this locks have my head spinning :-)
in any case this looks fishy:

static struct witness *
enroll(const char *description, struct lock_class *lock_class)
{
	struct witness *w;

	if (!witness_watch || witness_watch == 0 || panicstr != NULL)
            **************    ******************
		return (NULL);