ACPI/PCI: Reset acpi_root_dev->domain to 0 when pci_ignore_seg is set

Reset acpi_root_dev->domain to 0 when pci_ignore_seg is set to keep
consistence between ACPI PCI root device and PCI host bridge device.
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

arch/x86/pci/acpi.c

@@ -401,7 +401,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 	int node;
 
 	if (pci_ignore_seg)
-		domain = 0;
+		root->segment = domain = 0;
 
 	if (domain && !pci_domains_supported) {
 		printk(KERN_WARNING "pci_bus %04x:%02x: "