net/mlx4_en: Add support for destination MAC in steering rules

Implement destination MAC rule extension for L3/L4 rules in
flow steering. Usefull for vSwitch/macvlan configurations.

Signed-off-by: Yan Burman <yanb@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>