[PATCH] forcedeth: add recoverable error support

This patch adds support to recover from a previously fatal MAC error. In
the past the MAC would be hung on an internal fatal error. On new
chipsets, the MAC has the ability to enter a non-fatal state and allow
the driver to re-init it.

Signed-Off-By: Ayaz Abdulla <aabdulla@nvidia.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>