Registier Frequency to Kryo

Change-Id: I4e91c4f48197ed2aa46d6458e1f397eea3468b8f
diff --git a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
index a918e2d..034bcaf 100644
--- a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
+++ b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
@@ -210,6 +210,7 @@
             .register(new Ip6AddressSerializer(), Ip6Address.class)
             .register(new MacAddressSerializer(), MacAddress.class)
             .register(VlanId.class)
+            .register(Frequency.class)
             .build();
 
     /**