NFS: change nfs_writeback_done to return void

The return values are not used by any callers.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 6023efa..f88522b 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -501,7 +501,7 @@
 extern int  nfs_writepages(struct address_space *, struct writeback_control *);
 extern int  nfs_flush_incompatible(struct file *file, struct page *page);
 extern int  nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int);
-extern int nfs_writeback_done(struct rpc_task *, struct nfs_write_data *);
+extern void nfs_writeback_done(struct rpc_task *, struct nfs_write_data *);
 
 /*
  * Try to write back everything synchronously (but check the