irqchip: sun4i: Staticize sun4i_irq_ack()

sun4i_irq_ack() is only referenced in this file, so make it static.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Link: http://lkml.kernel.org/r/1373010070.14756.2.camel@phoenix
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/irqchip/irq-sun4i.c b/drivers/irqchip/irq-sun4i.c
index b66d4ae..a5438d8 100644
--- a/drivers/irqchip/irq-sun4i.c
+++ b/drivers/irqchip/irq-sun4i.c
@@ -38,7 +38,7 @@
 
 static asmlinkage void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs);
 
-void sun4i_irq_ack(struct irq_data *irqd)
+static void sun4i_irq_ack(struct irq_data *irqd)
 {
 	unsigned int irq = irqd_to_hwirq(irqd);
 	unsigned int irq_off = irq % 32;