bnx2x: add vlan filtering offload

Current driver always uses vlan-promisc mode, i.e., it receives both
tagged and untagged traffic and lets the network stack drop packets
tagged with unrequested vlan tags.

This patch implements vlan-filtering offload in the driver -
Unless explicitly configured to promisc mode, only untagged packets or
packets tagged with requested vlans would reach the Rx flow.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>