Use OpenMoko assigned MAC address range

[kevinmehall]

OpenMoko has assigned the Tessel Project a range of 8192 MAC addresses. The test rig should assign devices MAC addresses in this range instead of generating random addresses in the "Locally Administered" space.

The assigned range is: 00:1F:11:02:3a:00 to 00:1F:11:02:59:ff

The MAC addresses are written to the factory partition by the code here. It should query the server with the SAMD21 serial number to get a new MAC address assigned if this board has not been seen before, or re-use the same MAC if this board has already been tested. Keep the database mapping MACs to serial numbers as it may be useful later.

There are two MAC addresses in the factory partition for the WiFi and ethernet interfaces. However, I think OpenWrt may be reading only one of them and assigning the other sequentially, so experiment and match its behavior.