PCI: armada8k: Fix platform_get_irq() error handling

platform_get_irq() returns a negative number on failure, so adjust the
logic to detect such condition and propagate the real error value on
failure.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

drivers/pci/dwc/pcie-armada8k.c

@@ -176,9 +176,9 @@ static int armada8k_add_pcie_port(struct armada8k_pcie *pcie,
 	pp->ops = &armada8k_pcie_host_ops;
 
 	pp->irq = platform_get_irq(pdev, 0);
-	if (!pp->irq) {
+	if (pp->irq < 0) {
 		dev_err(dev, "failed to get irq for port\n");
-		return -ENODEV;
+		return pp->irq;
 	}
 
 	ret = devm_request_irq(dev, pp->irq, armada8k_pcie_irq_handler,