regulator: qcomm-labibb: replace use of system_wq with system_dfl_wq

Currently if a user enqueues a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistency cannot be addressed without refactoring the API.

This patch continues the effort to refactor worqueue APIs, which has begun
with the change introducing new workqueues and a new alloc_workqueue flag:

commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

This specific workload do not benefit from a per-cpu workqueue, so use
the default unbound workqueue (system_dfl_wq) instead.

Suggested-by: Tejun Heo <[e-mail]>
Signed-off-by: Marco Crivellari <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/qcom-labibb-regulator.c

···
 	return;
 
 reschedule:
-	mod_delayed_work(system_wq, &vreg->ocp_recovery_work,
+	mod_delayed_work(system_dfl_wq, &vreg->ocp_recovery_work,
 			 msecs_to_jiffies(OCP_RECOVERY_INTERVAL_MS));
 }
 
···
 	 * taking action is not truly urgent anymore.
 	 */
 	vreg->sc_count++;
-	mod_delayed_work(system_wq, &vreg->sc_recovery_work,
+	mod_delayed_work(system_dfl_wq, &vreg->sc_recovery_work,
 			 msecs_to_jiffies(SC_RECOVERY_INTERVAL_MS));
 }