management: Adding FaceFlags into nfd::FaceEventNotification

Change-Id: If7eb455a74c7802189667ccae649f78494cbded6
Refs: #1376
diff --git a/src/encoding/tlv-nfd.hpp b/src/encoding/tlv-nfd.hpp
index 7a84951..3e3c512 100644
--- a/src/encoding/tlv-nfd.hpp
+++ b/src/encoding/tlv-nfd.hpp
@@ -47,6 +47,7 @@
   TotalOutgoingDataCounter     = 147,
   FaceEventNotification        = 192,
   FaceEventKind                = 193,
+  FaceFlags                    = 194,
 
   // Forwarder status
   NfdVersion           = 128,