net/mlx5: Rename mlx5_comp_vectors_count() to mlx5_comp_vectors_max()

To accurately represent its purpose, rename the function that retrieves
the value of maximum vectors from mlx5_comp_vectors_count() to
mlx5_comp_vectors_max().

Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>