with the latest changes. They actually have valid ROM data at location
0 of memory, just like a real NE-2000 ISA card. Use this data, if
the ROM passes a few basic tests, as an additional source for the MAC
address. Prefer the CIS over this source, but have it take precidence
over falling back to reading the attribtue memory.
o Minor cleanup of a few devices that we match on based on CIS string.