internal PHY on the 3COM 3C905B and 3C905C parts, however I've rigged it so
that xlphy (aka exphy) takes precedence for the time being.
If people try this with their xl cards and decide that it's a better choice,
we can switch this later.
This is the PHY used in various iMacs and possibly other GMAC-equipped
Macintoshes with 10/100 PHYs (the ones with 10/100/1000 appear to use brgphy).
Obtained from: NetBSD
