NFS: Add event tracing for generic NFS lookups

Add tracepoints for lookup, lookup_revalidate and atomic_open

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfstrace.c b/fs/nfs/nfstrace.c
index cc91461..4eb0aea 100644
--- a/fs/nfs/nfstrace.c
+++ b/fs/nfs/nfstrace.c
@@ -2,6 +2,7 @@
  * Copyright (c) 2013 Trond Myklebust <Trond.Myklebust@netapp.com>
  */
 #include <linux/nfs_fs.h>
+#include <linux/namei.h>
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS