PCI: mvebu: Use for_each_available_child_of_node() to walk child nodes

Rather than using for_each_child_of_node() and testing each child's
availability, use the for_each_available_child_of_node() helper instead.

Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> (Armada XP GP)
Tested-by: Andrew Lunn <andrew@lunn.ch> (Kirkwood DIR665)
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

drivers/pci/host/pci-mvebu.c

@@ -978,13 +978,10 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	i = 0;
-	for_each_child_of_node(pdev->dev.of_node, child) {
+	for_each_available_child_of_node(pdev->dev.of_node, child) {
 		struct mvebu_pcie_port *port = &pcie->ports[i];
 		enum of_gpio_flags flags;
 
-		if (!of_device_is_available(child))
-			continue;
-
 		port->pcie = pcie;
 
 		if (of_property_read_u32(child, "marvell,pcie-port",