Set IPv6 DiffServ code point (DSCP) and MPLS EXP independently

One can now set the packet DSCP and MPLS EXP bits independently on IPv6 packets with MPC/MIC interfaces. To enable this feature, include the protocol mpls statement at the [edit class-of-service interfaces interface-name unit logical-unit rewrite-rules dscp-ipv6 rule-name] hierarchy level. One can set DSCP IPv6 values only at the ingress MPLS node.