nve locking fixes round 2

[David Xu]

John Baldwin wrote:

>Ok, now that the first set of locking overhaul is in the tree, can folks with 
>working nve(4) adapters test the patch referenced below and make sure there 
>are no regressions.  Having the IFF_UP fiddling turned off may or may not 
>help folks getting the TX timeouts as well, btw, so if people are feeling 
>brave they can try this patch as well.  Note it is only applicable to recent 
>current.
>
>http://www.FreeBSD.org/~jhb/patches/nve_locking.patch
>
>  
>
Make no difference on my AMD64 machine,dmesg:
http://people.freebsd.org/~davidxu/epox9nda3j.txt