soc/xilinx: replace use of system_unbound_wq with system_dfl_wq

Currently if a user enqueue 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 consistentcy 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 128ea9f ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea ("workqueue: Add new WQ_PERCPU flag")

system_dfl_wq should be the default workqueue so as not to enforce
locality constraints for random work whenever it's not required.

The old system_unbound_wq will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20251104103942.96647-1-marco.crivellari@suse.com

Author: DispatchCode

drivers/soc/xilinx/zynqmp_power.c

@@ -82,7 +82,7 @@ static void subsystem_restart_event_callback(const u32 *payload, void *data)
 	memcpy(zynqmp_pm_init_restart_work->args, &payload[0],
 	       sizeof(zynqmp_pm_init_restart_work->args));
 
-	queue_work(system_unbound_wq, &zynqmp_pm_init_restart_work->callback_work);
+	queue_work(system_dfl_wq, &zynqmp_pm_init_restart_work->callback_work);
 }
 
 static void suspend_event_callback(const u32 *payload, void *data)
@@ -95,7 +95,7 @@ static void suspend_event_callback(const u32 *payload, void *data)
 	memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
 	       sizeof(zynqmp_pm_init_suspend_work->args));
 
-	queue_work(system_unbound_wq, &zynqmp_pm_init_suspend_work->callback_work);
+	queue_work(system_dfl_wq, &zynqmp_pm_init_suspend_work->callback_work);
 }
 
 static irqreturn_t zynqmp_pm_isr(int irq, void *data)
@@ -140,7 +140,7 @@ static void ipi_receive_callback(struct mbox_client *cl, void *data)
 		memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
 		       sizeof(zynqmp_pm_init_suspend_work->args));
 
-		queue_work(system_unbound_wq,
+		queue_work(system_dfl_wq,
 			   &zynqmp_pm_init_suspend_work->callback_work);
 
 		/* Send NULL message to mbox controller to ack the message */