CORD-1622 CORD-1624 Add IPv6 mutlicast in McastHandler and OFDPA2.0 Drivers

Change-Id: Ibbb402b62999b39f8aea2cd236b959fc61fb94ac
(cherry picked from commit 65428c39e683cbd6314f40c4bf2c3ecff390addd)
diff --git a/utils/misc/src/main/java/org/onlab/packet/MacAddress.java b/utils/misc/src/main/java/org/onlab/packet/MacAddress.java
index e41fb05..b048794 100644
--- a/utils/misc/src/main/java/org/onlab/packet/MacAddress.java
+++ b/utils/misc/src/main/java/org/onlab/packet/MacAddress.java
@@ -56,6 +56,14 @@
      */
     public static final MacAddress IPV4_MULTICAST_MASK = valueOf("ff:ff:ff:80:00:00");
     /**
+     * IPv6 multicast MAC address.
+     */
+    public static final MacAddress IPV6_MULTICAST = valueOf("33:33:00:00:00:00");
+    /**
+     * IPv6 multicast MAC mask.
+     */
+    public static final MacAddress IPV6_MULTICAST_MASK = valueOf("FF:FF:00:00:00:00");
+    /**
      * A set of LLDP MAC addresses.
      */
     public static final Set<MacAddress> LLDP = ImmutableSet.of(