genirq: Use for_each_action_of_desc in actions_show()

Refactor action_show() to use for_each_action_of_desc instead
of a similar open-coded loop.
Signed-off-by: NParan Lee <p4ranlee@gmail.com>
[maz: reword commit message]
Signed-off-by: NMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220710112614.19410-1-p4ranlee@gmail.com

kernel/irq/irqdesc.c

@@ -251,7 +251,7 @@ static ssize_t actions_show(struct kobject *kobj,
 	char *p = "";
 
 	raw_spin_lock_irq(&desc->lock);
-	for (action = desc->action; action != NULL; action = action->next) {
+	for_each_action_of_desc(desc, action) {
 		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
 				 p, action->name);
 		p = ",";