drbd: Move write_ordering from mdev to tconn

This is necessary in order to prepare the move of the (receiver side)
epoch list from the device (mdev) to the connection (tconn) objects.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index b342c95..b369dd1 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1497,8 +1497,7 @@
 	new_disk_conf = NULL;
 	new_plan = NULL;
 
-	mdev->write_ordering = WO_bdev_flush;
-	drbd_bump_write_ordering(mdev, WO_bdev_flush);
+	drbd_bump_write_ordering(mdev->tconn, WO_bdev_flush);
 
 	if (drbd_md_test_flag(mdev->ldev, MDF_CRASHED_PRIMARY))
 		set_bit(CRASHED_PRIMARY, &mdev->flags);