ACPI: Remove unused struct acpi_pci_root.id member

This member is never initialized and never referenced, so remove it.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/acpi/acpi_bus.h

@@ -390,7 +390,6 @@ int unregister_acpi_bus_type(struct acpi_bus_type *);
 struct acpi_pci_root {
 	struct list_head node;
 	struct acpi_device * device;
-	struct acpi_pci_id id;
 	struct pci_bus *bus;
 	u16 segment;
 	struct resource secondary;	/* downstream bus range */