irqchip/brcmstb-l2: Make of probe function static

The probe functions in this driver is not exported or declared
so make it static to fix the following warning:

drivers/irqchip/irq-brcmstb-l2.c:115:12: warning: symbol 'brcmstb_l2_intc_of_init' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Link: https://lkml.kernel.org/r/1465408940-16414-1-git-send-email-ben.dooks@codethink.co.ukSigned-off-by: Jason Cooper <jason@lakedaemon.net>

drivers/irqchip/irq-brcmstb-l2.c

@@ -112,8 +112,8 @@ static void brcmstb_l2_intc_resume(struct irq_data *d)
 	irq_gc_unlock(gc);
 }
 
-int __init brcmstb_l2_intc_of_init(struct device_node *np,
-					struct device_node *parent)
+static int __init brcmstb_l2_intc_of_init(struct device_node *np,
+					  struct device_node *parent)
 {
 	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 	struct brcmstb_l2_intc_data *data;