[MIPS] IP27: Fix warning.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/sgi-ip27/ip27-timer.c

@@ -190,7 +190,7 @@ static struct irq_chip rt_irq_type = {
 };
 
 static struct irqaction rt_irqaction = {
-	.handler	= ip27_rt_timer_interrupt,
+	.handler	= (irq_handler_t) ip27_rt_timer_interrupt,
 	.flags		= IRQF_DISABLED,
 	.mask		= CPU_MASK_NONE,
 	.name		= "timer"