net/mlx5e: Specify SQ stats struct for mlx5e_open_txqsq()

Let the caller of mlx5e_open_txqsq() directly pass the SQ stats
structure pointer.
This replaces logic involving the qos_queue_group_id parameter,
and helps generalizing its role in the next patch.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>