ONOS-7810 calculate cookie field when pipeconf registered

Change-Id: Iea29fc447b34c49d4e8fcc831812385459c1ccbb
(cherry picked from commit ec1a420030d2ecab77909056a34aee50f808f72f)
diff --git a/core/api/src/main/java/org/onosproject/net/pi/model/PiPipeconf.java b/core/api/src/main/java/org/onosproject/net/pi/model/PiPipeconf.java
index 5fedaf7..e3664e1 100644
--- a/core/api/src/main/java/org/onosproject/net/pi/model/PiPipeconf.java
+++ b/core/api/src/main/java/org/onosproject/net/pi/model/PiPipeconf.java
@@ -45,6 +45,13 @@
     PiPipelineModel pipelineModel();
 
     /**
+     * Returns the fingerprint of pipeconf.
+     *
+     * @return a fingerprint
+     */
+    long fingerprint();
+
+    /**
      * Returns all pipeline-specific behaviour interfaces defined by this configuration.
      *
      * @return a collection of behaviours