3c900B-TPC (twisted pair and coax). Treated similarly to the
3c900B-COMBO, except no AUI port.
- Fix media selection so that it's possible to select the AUI and BNC
ports on the 3c905B-COMBO. This board is now fully supported.
- Change TX queueing strategy to hopefully be more efficient by avoiding
register accesses in xl_start(). Should provide small performance
improvement and a little better reliability.