Optimise and fix tristate interface to PHY. Add link to PHY specific ethtool commands

Created by: jrrk

This patch allows ethtool PHY commands to work.

e.g. ethtool -s eth0 advertise 0xf

which is confirmed from the following output:

ethtool eth0

Settings for eth0: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supported pause frame use: Symmetric Receive-only Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Link partner advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full Link partner advertised pause frame use: No Link partner advertised auto-negotiation: Yes Link partner advertised FEC modes: Not reported Speed: 100Mb/s Duplex: Full Port: MII PHYAD: 1 Transceiver: internal Auto-negotiation: on

This is accomplished by the following changes:

Alter polarity of tri-state control to MDIO to compensate for hardware signal named incorrectly. Link ethtool commands through to PHY layer. Optimise bit-bang code (probably not necessary). Remove obsolete declarations from driver header file.