ARM: amba: make use of -1 IRQs warn

Make the core warn about the use of -1 (NO_IRQ)

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index d15acbb..01c2cf4 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -511,6 +511,9 @@
 	void __iomem *tmp;
 	int i, ret;
 
+	WARN_ON(dev->irq[0] == (unsigned int)-1);
+	WARN_ON(dev->irq[1] == (unsigned int)-1);
+
 	ret = request_resource(parent, &dev->res);
 	if (ret)
 		goto err_out;