irqchip/orion: Use of_address_count() helper

After commit 16988c74 ("of/address: introduce of_address_count() helper"),
Use of_address_count() to instead of open-coding it, it's no functional change.
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230726030741.1136244-1-yangyingliang@huawei.com

drivers/irqchip/irq-orion.c

@@ -57,8 +57,7 @@ static int __init orion_irq_init(struct device_node *np,
 	struct resource r;
 
 	/* count number of irq chips by valid reg addresses */
-	while (of_address_to_resource(np, num_chips, &r) == 0)
-		num_chips++;
+	num_chips = of_address_count(np);
 
 	orion_irq_domain = irq_domain_add_linear(np,
 				num_chips * ORION_IRQS_PER_CHIP,