irqchip: bcm7120-l2: Fix error handling of irq_of_parse_and_map

Return value of irq_of_parse_and_map() is unsigned int, with 0
indicating failure, so testing for negative result never works.

Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Kevin Cernekee <cernekee@gmail.com>
Link: https://lkml.kernel.org/r/20141114221614.GA37395@dtor-ws
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/drivers/irqchip/irq-bcm7120-l2.c b/drivers/irqchip/irq-bcm7120-l2.c
index b9f4fb8..5fb38a2 100644
--- a/drivers/irqchip/irq-bcm7120-l2.c
+++ b/drivers/irqchip/irq-bcm7120-l2.c
@@ -101,9 +101,9 @@
 	int parent_irq;
 
 	parent_irq = irq_of_parse_and_map(dn, irq);
-	if (parent_irq < 0) {
+	if (!parent_irq) {
 		pr_err("failed to map interrupt %d\n", irq);
-		return parent_irq;
+		return -EINVAL;
 	}
 
 	data->irq_map_mask |= be32_to_cpup(map_mask + irq);