irqchip/i8259: Prepare i8259_irq_dispatch for irq argument removal

Make irq a local variable and retrieve domain from the irq descriptor
which avoid a redundant lookup.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>

drivers/irqchip/irq-i8259.c

@@ -352,10 +352,11 @@ void __init init_i8259_irqs(void)
 	__init_i8259_irqs(NULL);
 }
 
-static void i8259_irq_dispatch(unsigned int irq, struct irq_desc *desc)
+static void i8259_irq_dispatch(unsigned int __irq, struct irq_desc *desc)
 {
-	struct irq_domain *domain = irq_get_handler_data(irq);
+	struct irq_domain *domain = irq_desc_get_handler_data(desc);
 	int hwirq = i8259_irq();
+	unsigned int irq;
 
 	if (hwirq < 0)
 		return;