net/mlx5: Update access functions to Query/Modify vport MAC address

In preparation for SR-IOV we add here an API to enable each e-switch
client (PF/VF) to configure its L2 MAC addresses and for the e-switch
manager (usually the PF) to access them in order to be able to
configure them into the e-switch.
Therefore we now pass vport num parameter to
mlx5_query_nic_vport_context, so PF can access other vports contexts.

preperation for ethernet sriov and l2 table management.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>