irqchip/realtek-rtl: use irq_domain_add_linear()

When using an offset of 0, irq_domain_add_simple() is identical to
irq_domain_add_linear() on DT-based systems, so use the latter instead.
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/0c4cd9f7661a30a4cb7ab9881c4a94bc8a379162.1663617425.git.sander@svanheule.net

drivers/irqchip/irq-realtek-rtl.c

@@ -171,8 +171,7 @@ static int __init realtek_rtl_of_init(struct device_node *node, struct device_no
 	/* Disable all cascaded interrupts */
 	writel(0, REG(RTL_ICTL_GIMR));
 
-	domain = irq_domain_add_simple(node, 32, 0,
-				       &irq_domain_ops, NULL);
+	domain = irq_domain_add_linear(node, 32, &irq_domain_ops, NULL);
 
 	ret = map_interrupts(node, domain);
 	if (ret) {