NFSv4: Further clean-ups of delegation stateid validation

Change the name to reflect what we're really doing: testing two
stateids for whether or not they match according the the rules in
RFC3530 and RFC5661.
Move the code from callback_proc.c to nfs4proc.c

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index c14512c..c7249e2 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -556,7 +556,7 @@
 	rcu_read_lock();
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
 
-	if (!clp->cl_mvops->validate_stateid(delegation, stateid)) {
+	if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) {
 		rcu_read_unlock();
 		return -ENOENT;
 	}