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: Paran Lee <[e-mail]>
[maz: reword commit message]
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

kernel/irq/irqdesc.c

···
 	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 = ",";