NFSv4: Cleanup the setting of the nfs4 lease period

Make a helper function nfs4_set_lease_period() and have
nfs41_setup_state_renewal() and nfs4_do_fsinfo() use it.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index da5c9e5..b9e1867 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4237,12 +4237,9 @@
 		err = _nfs4_do_fsinfo(server, fhandle, fsinfo);
 		trace_nfs4_fsinfo(server, fhandle, fsinfo->fattr, err);
 		if (err == 0) {
-			struct nfs_client *clp = server->nfs_client;
-
-			spin_lock(&clp->cl_lock);
-			clp->cl_lease_time = fsinfo->lease_time * HZ;
-			clp->cl_last_renewal = now;
-			spin_unlock(&clp->cl_lock);
+			nfs4_set_lease_period(server->nfs_client,
+					fsinfo->lease_time * HZ,
+					now);
 			break;
 		}
 		err = nfs4_handle_exception(server, err, &exception);