[PATCH] emac: add support for platform-specific unsupported PHY features

This patch adds support to the ibm_emac driver for platform-specific
unsupported PHY features.

The patch attempts to determine the highest speed and duplex when
autonegotiation is unsupported.

Signed-off-by: Wade Farnsworth <wfarnsworth@mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>