PCI: Wait 1 second between disabling VFs and clearing NumVFs

Per sec 3.3.3.1 of the SR-IOV spec, r1.1, we must allow 1.0s after clearing
VF Enable before reading any field in the SR-IOV Extended Capability.

Wait 1 second before calling pci_iov_set_numvfs(), which reads
PCI_SRIOV_VF_OFFSET and PCI_SRIOV_VF_STRIDE after it sets PCI_SRIOV_NUM_VF.

[bhelgaas: split to separate patch for reviewability, add spec reference]
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/iov.c

@@ -339,13 +339,13 @@ failed:
 	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFE | PCI_SRIOV_CTRL_MSE);
 	pci_cfg_access_lock(dev);
 	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
-	pci_iov_set_numvfs(dev, 0);
 	ssleep(1);
 	pci_cfg_access_unlock(dev);
 
 	if (iov->link != dev->devfn)
 		sysfs_remove_link(&dev->dev.kobj, "dep_link");
 
+	pci_iov_set_numvfs(dev, 0);
 	return rc;
 }