PCI: xgene: Request host bridge window resources

Request host bridge window resources so they appear in ioport_resource and
iomem_resource and are reflected in /proc/ioports and /proc/iomem.

For example, the following entries did not previously appear in /proc/iomem:

  e180000000-e1ffffffff : /soc/pcie@1f2b0000
    e180000000-e182ffffff : PCI Bus 0000:01
      e180000000-e181ffffff : 0000:01:00.0
      e182000000-e1820fffff : 0000:01:00.0
      e182100000-e1821fffff : 0000:01:00.0
  f000000000-ffffffffff : /soc/pcie@1f2b0000
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/host/pci-xgene.c

@@ -540,6 +540,10 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = devm_request_pci_bus_resources(&pdev->dev, &res);
+	if (ret)
+		goto error;
+
 	ret = xgene_pcie_setup(port, &res, iobase);
 	if (ret)
 		goto error;