net/mlx5: SF, Store and use start function id

SF ids in the device are in two different contiguous ranges. One for
the local controller and second for the external host controller.

Prepare code to handle multiple start function id by storing it in the
table.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Vu Pham <vuhuong@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>