[PATCH] forcedeth: add mgmt unit support

This patch adds support for the mgmt unit in certain chipsets. The MAC
and the mgmt unit share the PHY and therefore proper intialization
procedures are needed for them to maintain coexistense.

Signed-Off-By: Ayaz Abdulla <aabdulla@nvidia.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>