PCI: xilinx: Fix return value in case of error

In xilinx_pcie_init_irq_domain(), the pattern used to check and return
error is:

   if (!var) {
      dev_err(...);
      return PTR_ERR(var);
   }

So the returned value in case of error is always 0, which means 'success'.
Change it to return -ENODEV instead.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Sören Brinkmann <soren.brinkmann@xilinx.com>

drivers/pci/host/pcie-xilinx.c

@@ -550,15 +550,15 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
 	pcie_intc_node = of_get_next_child(node, NULL);
 	if (!pcie_intc_node) {
 		dev_err(dev, "No PCIe Intc node found\n");
-		return PTR_ERR(pcie_intc_node);
+		return -ENODEV;
 	}
 
 	port->irq_domain = irq_domain_add_linear(pcie_intc_node, 4,
 						 &intx_domain_ops,
 						 port);
 	if (!port->irq_domain) {
 		dev_err(dev, "Failed to get a INTx IRQ domain\n");
-		return PTR_ERR(port->irq_domain);
+		return -ENODEV;
 	}
 
 	/* Setup MSI */
@@ -569,7 +569,7 @@ static int xilinx_pcie_init_irq_domain(struct xilinx_pcie_port *port)
 							 &xilinx_pcie_msi_chip);
 		if (!port->irq_domain) {
 			dev_err(dev, "Failed to get a MSI IRQ domain\n");
-			return PTR_ERR(port->irq_domain);
+			return -ENODEV;
 		}
 
 		xilinx_pcie_enable_msi(port);