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

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

include/linux/nfs_xdr.h

@@ -1133,7 +1133,6 @@ struct nfs_page;
 #define NFS_PAGEVEC_SIZE	(8U)
 
 struct nfs_read_data {
-	int			flags;
 	struct rpc_task		task;
 	struct inode		*inode;
 	struct rpc_cred		*cred;