Adding optional initial vector to EncryptedContent

Refs: #3013

Change-Id: I1c6fea3552796d13525d33e3a9d385156e2d463e
diff --git a/src/tlv.hpp b/src/tlv.hpp
index 92f2f4e..a94af47 100644
--- a/src/tlv.hpp
+++ b/src/tlv.hpp
@@ -29,7 +29,8 @@
 enum {
   EncryptedContent = 130,
   EncryptionAlgorithm = 131,
-  EncryptedPayload = 132
+  EncryptedPayload = 132,
+  InitialVector = 133
 };
 
 enum AlgorithmTypeValue {