used in the SMC EtherPower II.
Media control isn't yet supported, due to some MII infrastructure
problems which I hope to address soon. This isn't a huge deal, since
the PHY defaults to auto-negotiate mode.
Also, the device just programs the multicast hash table to accept all
multicast, to avoid a hardware bug that causes the multicast address
filter to lose in 10Mb/s mode. This bug will be fixed in a more sane
way once the media control issues are dealt with.
thorpej