nfsd: eliminate cl_ra_cblist and NFSD4_CLIENT_CB_RECALL_ANY

nfsd: eliminate cl_ra_cblist and NFSD4_CLIENT_CB_RECALL_ANY

deleg_reaper() will walk the client_lru list and put any suitable
entries onto "cblist" using the cl_ra_cblist pointer. It then walks the
objects outside the spinlock and queues callbacks for them.

None of the operations that deleg_reaper() does outside the
nn->client_lock are blocking operations. Just queue their workqueue jobs
under the nn->client_lock instead.

Also, the NFSD4_CLIENT_CB_RECALL_ANY and NFSD4_CALLBACK_RUNNING flags
serve an identical purpose now. Drop the NFSD4_CLIENT_CB_RECALL_ANY flag
and just use the one in the callback.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>