ocfs2: Remove mlog(0) from fs/ocfs2/heartbeat.c

This is the 2nd step to remove the debug info of SUPER.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>

diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h
index d70471f..876b119d 100644
--- a/fs/ocfs2/ocfs2_trace.h
+++ b/fs/ocfs2/ocfs2_trace.h
@@ -1530,6 +1530,13 @@
 DEFINE_OCFS2_INT_EVENT(ocfs2_find_slot);
 
 /* End of trace events for fs/ocfs2/slot_map.c. */
+
+/* Trace events for fs/ocfs2/heartbeat.c. */
+
+DEFINE_OCFS2_INT_EVENT(ocfs2_do_node_down);
+
+/* End of trace events for fs/ocfs2/heartbeat.c. */
+
 #endif /* _TRACE_OCFS2_H */
 
 /* This part must be outside protection */