dcb: add DCBX mode to event notifier attributes

Add DCBX mode to event notifiers so listeners can learn
currently enabled mode.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dcbnl.h b/include/net/dcbnl.h
index 263aa3a..2cd66d0 100644
--- a/include/net/dcbnl.h
+++ b/include/net/dcbnl.h
@@ -26,6 +26,7 @@
 	int	ifindex;
 	struct dcb_app	  app;
 	struct list_head  list;
+	u8	dcbx;
 };
 
 int dcb_setapp(struct net_device *, struct dcb_app *);