PCI: spear13xx: 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: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Pratyush Anand <pratyush.anand@gmail.com>

drivers/pci/dwc/pcie-spear13xx.c

@@ -199,9 +199,9 @@ static int spear13xx_add_pcie_port(struct spear13xx_pcie *spear13xx_pcie,
 	int ret;
 
 	pp->irq = platform_get_irq(pdev, 0);
-	if (!pp->irq) {
+	if (pp->irq < 0) {
 		dev_err(dev, "failed to get irq\n");
-		return -ENODEV;
+		return pp->irq;
 	}
 	ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
 			       IRQF_SHARED | IRQF_NO_THREAD,