Add support for the 3c656B cardbus adapter. This is one half of a
dual function card. It needs pretty much the same flags as the 656C,
except that it seems to need both the INVERT_MII_PWR and INVERT_LED_PWR
flags set. Tested with cardbus in -current as of today.

Also added support for the 3c656, which looks to be the same as
the 656B, except it doesn't need the EEPROM_8BIT flag. I think. This
one is untested, but the added support should not break any of the
other cards.