net/mlx5e: Make mlx5e_tc_table private

Move mlx5e_tc_table struct to en_tc.c thus make it private.
Introduce allocation and deallocation functions as part of the tc API
to allow this switch smoothly.

Convert mlx5e_nic_chain() macro to a function of en_tc.c.

Signed-off-by: Lama Kayal <lkayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>