direct_IO: remove rw from a_ops->direct_IO()

Now that no one is using rw, remove it completely.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index fd5599d..155ab9c 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1198,8 +1198,7 @@
  * intercept O_DIRECT reads and writes early, this function should
  * never get called.
  */
-static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
-			      struct iov_iter *iter,
+static ssize_t ceph_direct_io(struct kiocb *iocb, struct iov_iter *iter,
 			      loff_t pos)
 {
 	WARN_ON(1);