kernel - Refactor lockmgr() (2)

kernel - Refactor lockmgr() (2)

* Remove the global vfs_spin() lock and single vnode_active_list
  and single vnode_inactive_list.

* Replace with a pcpu array of spinlocks and lists.  However, for
  this initial push the array is simply hashed based on the vnode
  pointer, so it isn't really being acted on pcpu.

* Significantly reduces numerous bottlenecks when vnodes start to get
  recycled by vnlru().  Cache line bounces are still a problem,
  but direct spinlock conflicts are essentially gone.