PCI: Clean up resource allocation in devm_of_pci_get_host_bridge_resources()

Instead of first allocating and then freeing memory for struct resource in
case we cannot parse a PCI resource from the device tree, work against a
local struct and kmemdup() it when we decide to go with it.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>

drivers/pci/of.c

@@ -266,7 +266,7 @@ int devm_of_pci_get_host_bridge_resources(struct device *dev,
 			struct list_head *resources, resource_size_t *io_base)
 {
 	struct device_node *dev_node = dev->of_node;
-	struct resource *res;
+	struct resource *res, tmp_res;
 	struct resource *bus_range;
 	struct of_pci_range range;
 	struct of_pci_range_parser parser;
@@ -320,18 +320,16 @@ int devm_of_pci_get_host_bridge_resources(struct device *dev,
 		if (range.cpu_addr == OF_BAD_ADDR || range.size == 0)
 			continue;
 
-		res = devm_kzalloc(dev, sizeof(struct resource), GFP_KERNEL);
+		err = of_pci_range_to_resource(&range, dev_node, &tmp_res);
+		if (err)
+			continue;
+
+		res = devm_kmemdup(dev, &tmp_res, sizeof(tmp_res), GFP_KERNEL);
 		if (!res) {
 			err = -ENOMEM;
 			goto failed;
 		}
 
-		err = of_pci_range_to_resource(&range, dev_node, res);
-		if (err) {
-			devm_kfree(dev, res);
-			continue;
-		}
-
 		if (resource_type(res) == IORESOURCE_IO) {
 			if (!io_base) {
 				dev_err(dev, "I/O range found for %pOF. Please provide an io_base pointer to save CPU base address\n",