net/mlx5: EQ, Privatize eq_table and friends

Move unnecessary EQ table structures and declaration from the
public include/linux/mlx5/driver.h into the private area of mlx5_core
and into eq.c/eq.h.

Introduce new mlx5 EQ APIs:

mlx5_comp_vectors_count(dev);
mlx5_comp_irq_get_affinity_mask(dev, vector);

And use them from mlx5_ib or mlx5e netdevice instead of direct access to
mlx5_core internal structures.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>