net/mlx5: Provide cpumask at EQ creation phase

The users of EQ are running their code on different CPUs and with
various affinity patterns. Move the cpumask setting close to their
actual usage.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>