net/enic: fix MAC address add and remove

net/enic: 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.

Fixes: fefed3d1e62c ("enic: new driver")

Signed-off-by: John Daley <johndale@cisco.com>
Reviewed-by: Nelson Escobar <neescoba@cisco.com>