PM / Domains: don't use [delayed_]work_pending()

There's no need to test whether a (delayed) work item is pending
before queueing, flushing or cancelling it, so remove work_pending()
tests used in those cases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -433,7 +433,6 @@ static bool genpd_abort_poweroff(struct generic_pm_domain *genpd)
  */
 void genpd_queue_power_off_work(struct generic_pm_domain *genpd)
 {
-	if (!work_pending(&genpd->power_off_work))
 	queue_work(pm_wq, &genpd->power_off_work);
 }