PCI: Finish SR-IOV VF setup before adding the device

Commit 4f535093 "PCI: Put pci_dev in device tree as early as possible"
moves device registering from pci_bus_add_devices() to pci_device_add().
That causes problems for virtual functions because device_add(&virtfn->dev)
is called before setting the virtfn->is_virtfn flag, which then causes Xen
to report PCI virtual functions as PCI physical functions.

Fix it by setting virtfn->is_virtfn before calling pci_device_add().

[Jiang Liu]: Move the setting of virtfn->is_virtfn ahead further for better
readability and modify changelog.
Signed-off-by: NXudong Hao <xudong.hao@intel.com>
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org	# v3.9+

drivers/pci/iov.c

@@ -92,6 +92,8 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
 	pci_read_config_word(dev, iov->pos + PCI_SRIOV_VF_DID, &virtfn->device);
 	pci_setup_device(virtfn);
 	virtfn->dev.parent = dev->dev.parent;
+	virtfn->physfn = pci_dev_get(dev);
+	virtfn->is_virtfn = 1;
 
 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 		res = dev->resource + PCI_IOV_RESOURCES + i;
@@ -113,9 +115,6 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
 	pci_device_add(virtfn, virtfn->bus);
 	mutex_unlock(&iov->dev->sriov->lock);
 
-	virtfn->physfn = pci_dev_get(dev);
-	virtfn->is_virtfn = 1;
-
 	rc = pci_bus_add_device(virtfn);
 	sprintf(buf, "virtfn%u", id);
 	rc = sysfs_create_link(&dev->dev.kobj, &virtfn->dev.kobj, buf);