lp: add TxSequence field

refs #3931

Change-Id: Ie388ec48494b8ac506b31dc42de8777a8cd28989
diff --git a/src/lp/tlv.hpp b/src/lp/tlv.hpp
index 4ef0c9b..0fd782e 100644
--- a/src/lp/tlv.hpp
+++ b/src/lp/tlv.hpp
@@ -42,7 +42,8 @@
   CachePolicyType = 821,
   IncomingFaceId = 817,
   CongestionMark = 832,
-  Ack = 836
+  Ack = 836,
+  TxSequence = 840
 };
 
 enum {