ENIC driver patch to fix MAC address add and remove

The mac_addr_add callback function was simply replacing the primary MAC
address instead of adding new ones and the mac_addr_remove callback would
only remove the primary MAC form the adapter. Fix the functions to add or
remove new address. Allow up to 64 MAC addresses per port.

Change-Id: Ieff396ae27505c4c09f028911eff907757b03c7d
Signed-off-by: Steve Shin <jonshin@cisco.com>