[PATCH 7/7 V2] workqueue: add get_node_unbound_pwq()

The calculation and allocation of per-node pwq code in apply_workqueue_attrs() and wq_update_unbound_numa() are highly similar, we merge them into get_node_unbound_pwq(). wq_calc_node_mask() is only used for this calculation and allocation, so it is also moved into get_node_unbound_pwq(). The

[PATCH 7/7 V2] workqueue: add get_node_unbound_pwq()

The calculation and allocation of per-node pwq code in apply_workqueue_attrs() and wq_update_unbound_numa() are highly similar, we merge them into get_node_unbound_pwq(). wq_calc_node_mask() is only used for this calculation and allocation, so it is also moved into get_node_unbound_pwq(). The