nfs: propagate devname to nfs{,4}_get_root()

step 1 of ->mnt_devname fixes: make sure we have the value of devname
available in ..._get_root().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index cf9fdbd..9e5a003 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -254,9 +254,11 @@
 extern struct vfsmount *nfs_d_automount(struct path *path);
 
 /* getroot.c */
-extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *);
+extern struct dentry *nfs_get_root(struct super_block *, struct nfs_fh *,
+				   const char *);
 #ifdef CONFIG_NFS_V4
-extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *);
+extern struct dentry *nfs4_get_root(struct super_block *, struct nfs_fh *,
+				    const char *);
 
 extern int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh);
 #endif