NFS: Get rid of the unused nfs_write_data->flags field

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/nfs_xdr.h

@@ -1155,7 +1155,6 @@ struct nfs_read_data {
 };
 
 struct nfs_write_data {
-	int			flags;
 	struct rpc_task		task;
 	struct inode		*inode;
 	struct rpc_cred		*cred;