Eoe mac address now derived from unique mac.
The EoE MAC address is now derived from the NIC part of the first global
unique MAC address of the linked list of available network interfaces or
otherwise the MAC address used by the EtherCAT master. The EoE MAC address
will get the format 02:NIC:NIC:NIC:RP:RP where NIC comes from the unique MAC
address (if available) and RP is the ring position of the EoE slave.