mfd: arizona: Fix lockdep recursion warning on set_irq_wake

Avoid a false recursive locking warning from lockdep by adding a lock
class for the arizona IRQ chip.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/arizona-irq.c

@@ -168,12 +168,15 @@ static struct irq_chip arizona_irq_chip = {
 	.irq_set_wake		= arizona_irq_set_wake,
 };
 
+static struct lock_class_key arizona_irq_lock_class;
+
 static int arizona_irq_map(struct irq_domain *h, unsigned int virq,
 			      irq_hw_number_t hw)
 {
 	struct arizona *data = h->host_data;
 
 	irq_set_chip_data(virq, data);
+	irq_set_lockdep_class(virq, &arizona_irq_lock_class);
 	irq_set_chip_and_handler(virq, &arizona_irq_chip, handle_simple_irq);
 	irq_set_nested_thread(virq, 1);
 	irq_set_noprobe(virq);