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>

fs/ext3/inode.c

@@ -1820,8 +1820,8 @@ static int ext3_releasepage(struct page *page, gfp_t wait)
  * crashes then stale disk data _may_ be exposed inside the file. But current
  * VFS code falls back into buffered path in that case so we are safe.
  */
-static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
-			struct iov_iter *iter, loff_t offset)
+static ssize_t ext3_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+			      loff_t offset)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;