forcedeth bug fix: realtek phy 8211c errata

This patch adds support for the realtek 8211c phy. The driver must
perform a hardware reset of the phy due to an errata where the phy could
not detect the link.

Signed-off-by: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>