Regard the release when the APIs became deprecated as Cardinal

Change-Id: I072fa33a2a70baa7466d7a0dc5067191476be0f3
diff --git a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
index 9703e1c..e8101f1 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/instructions/Instructions.java
@@ -284,6 +284,7 @@
      *
      * @param etherType Ethernet type to set
      * @return a L2 modification.
+     * @deprecated in Cardinal Release
      */
     @Deprecated
     public static Instruction popMpls(int etherType) {