Prevent packets duplication for frames targeting FCoE L2 ring:
packets were arriving to stack from both L2 RSS and from FCoE
L2 in a promiscuous mode.

Configure FCoE L2 ring to DROP_ALL rx mode, when interface is
configured to PROMISC, and to accept only unicast frames, when
interface is configured to ALL_MULTI.
Signed-off-by: NVladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>