net/mlx5: Lag, use actual number of lag ports

Refactor the entire lag code to use ldev->ports instead of hard-coded
defines (like MLX5_MAX_PORTS) for its operations.

Signed-off-by: Mark Bloch <[email protected]>
Reviewed-by: Maor Gottlieb <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: mark-bloch