net/mlx5: Configure IB devices according to LAG state

When mlx5_ib is loaded, we would like each card's IB devices
to be added according to its LAG state (one IB device, instead of
two, is to be added if LAG is active).

Signed-off-by: Aviv Heller <avivh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>