on certain boards (like the pcduino) u-boot doesn't setup the MAC address for us, in this case calculate an address based on the Security ID (SID) to ensure we get a unique address.
on certain boards (like the pcduino) u-boot doesn't setup the MAC address for
us, in this case calculate an address based on the Security ID (SID) to ensure
we get a unique address.

tested on pcduino to ensure a unique address and verified by aalm@ on cubieboard
(where u-boot does setup the MAC address).

ok aalm@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars