NFS: struct nfs_open_dir_context: convert rpc_cred pointer to cred.

Use the common 'struct cred' to pass credentials for readdir.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 7d2064b..271015e 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -89,7 +89,7 @@
 
 struct nfs_open_dir_context {
 	struct list_head list;
-	struct rpc_cred *cred;
+	const struct cred *cred;
 	unsigned long attr_gencount;
 	__u64 dir_cookie;
 	__u64 dup_cookie;