net/mlx5: Remove redundant SF supported check from mlx5_sf_hw_table_init()

Since mlx5_sf_supported() check is done as a first thing in
mlx5_sf_max_functions(), remove the redundant check.

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