interface: callback to manage extra MAC addresses

interface: callback to manage extra MAC addresses

Type: feature

New callback vnet_hw_interface_add_del_mac_address().

Add or delete secondary MAC addresses on a hardware interface.
This will allow packets to be processed which have a destination
MAC address other than the primary programmed MAC address without
needing to put the device into promiscuous mode.

Change-Id: I6beecbcb8932fc1fe45b567f76fa3706feefae2c
Signed-off-by: Matthew Smith <mgsmith@netgate.com>