bnx2x: add afex support

Following patch adds afex multifunction support to the driver (afex
multifunction is based on vntag header) and updates FW version used to 7.2.51.

Support includes the following:

1. Configure vif parameters in firmware (default vlan, vif id, default
   priority, allowed priorities) according to values received from NIC.
2. Configure FW to strip/add default vlan according to afex vlan mode.
3. Notify link up to OS only after vif is fully initialized.
4. Support vif list set/get requests and configure FW accordingly.
5. Supply afex statistics upon request from NIC.
6. Special handling to L2 interface in case of FCoE vif.

Signed-off-by: Barak Witkowski <barak@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>