net/mlx5: Introduce access functions to modify/query vport state

net/mlx5: Introduce access functions to modify/query vport state

BugLink: http://bugs.launchpad.net/bugs/1540435
In preparation for SR-IOV we add here an API to enable each e-switch
manager (PF) to configure its VFs link states in e-switch

preparation for ethernet sriov.

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>
(cherry picked from commit e75465148b7df7f2796c75bf98bf33f171edeb2b)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>