net/mlx5: Remove redundant max_sfs check and field from struct mlx5_sf_dev_table

table->max_sfs is initialized in mlx5_sf_dev_table_create() and only
used to check for 0 in mlx5_sf_dev_add(). mlx5_sf_dev_add() is called
either from mlx5_sf_dev_state_change_handler() or
mlx5_sf_dev_add_active_work(). Both ensure max SF count is not 0,
using mlx5_sf_max_functions() helper before calling mlx5_sf_dev_add().

So remove the redundant check and no longer used max_sfs field.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>