PCI fast ethernet controller. Currently, the only card I know that uses
this chip is the D-Link DFE-550TX. (Don't ask me where to buy these: the
only cards I have are samples sent to me by D-Link.)
This driver is the first to make use of the miibus code once I'm sure
it all works together nicely, I'll start converting the other drivers.
The Sundance chip is a clone of the 3Com 3c90x Etherlink XL design
only with its own register layout. Support is provided for ifmedia,
hardware multicast filtering, bridging and promiscuous mode.