Added SerializeTo to LinkLayerDiscovery to statisfy SerializableLayer interface. ChassisID now satisfies a new interface LLDPSerializableTLV which ensures that each TLV is responsible for its own serialization
Added SerializeTo to LinkLayerDiscovery to statisfy SerializableLayer interface. ChassisID now satisfies a new interface LLDPSerializableTLV which ensures that each TLV is responsible for its own serialization

google/gopacket,google/gopacket,google/gopacket