PCI: keystone: 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>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-By: Murali Karicheri <m-karicheri2@ti.com>

drivers/pci/host/pci-keystone.c

@@ -197,7 +197,7 @@ static int ks_pcie_get_irq_controller_info(struct keystone_pcie *ks_pcie,
 	 */
 	for (temp = 0; temp < max_host_irqs; temp++) {
 		host_irqs[temp] = irq_of_parse_and_map(*np_temp, temp);
-		if (host_irqs[temp] < 0)
+		if (!host_irqs[temp])
 			break;
 	}
 	if (temp) {