bnx2x: use SAN Mac for FCoE.

Current logic causes chips running in switch dependent multi-function
FCoE mode not to configure their MAC, leading to an all 0s MAC.

This patch configures the interface with the SAN Mac instead.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>