bnx2x: Add remote-fault link detection

Restore remote-faule detection, which periodically checks for
remote-fault on the MAC layer. In case physical link appear to be
up but fault is set, it will provide a link down indication, and
when the fault is cleared, it will indicate link up again.

Signed-off-by: Yaniv Rosner <yaniv.rosner@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>