direct-io: eliminate the offset argument to ->direct_IO

Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/udf/file.c b/fs/udf/file.c
index 877ba1c..7ab8d81 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -99,8 +99,7 @@
 	return 0;
 }
 
-static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				     loff_t offset)
+static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	/* Fallback to buffered I/O. */
 	return 0;