block,fs: use REQ_* flags directly

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b5b9bff..33c435f 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1304,7 +1304,7 @@ _xfs_buf_ioapply(
 	if (bp->b_flags & XBF_WRITE) {
 		op = REQ_OP_WRITE;
 		if (bp->b_flags & XBF_SYNCIO)
-			op_flags = WRITE_SYNC;
+			op_flags = REQ_SYNC;
 		if (bp->b_flags & XBF_FUA)
 			op_flags |= REQ_FUA;
 		if (bp->b_flags & XBF_FLUSH)