hammer2 - Initial CCMS locking tie-in

hammer2 - Initial CCMS locking tie-in

This is a necessary precursor step to being able to integrate the cache
state grants with our chain locks.  Basically we are replacing the
hammer2 chain lockmgr lock (hammer2_chain->lk) with a CCMS cst structure
(hammer2_chain->cst).

This structure will become the attribute CST for hammer2 inodes.  The
topological CST is built into the hammer2_inode.  Data-space CSTs will
initially be the hammer2_chain->cst for indirect blocks though we will
probably also need one or more in hammer2_inode to handle generic casess.