config: yoshino: Enable WQ_POWER_EFFICIENT_DEFAULT

Per-cpu workqueues are generally preferred because they show better performance thanks to cache locality; unfortunately, per-cpu workqueues tend to be more power hungry than unbound workqueues.

Enabling workqueue.power_efficient kernel parameter makes the per-cpu workqueues which were observed to contribute significantly to power consumption unbound, leading to measurably lower power usage at the cost of small performance overhead.

This config option determines whether workqueue.power_efficient is enabled by default.