PCI: allow PCI core hotplug to remove PCI root bus

There is no reason to prevent removal of root bus devices. A subsequent
rescan will find them just fine.

Reviewed-by: Kenji Kaneshige <[e-mail]>
Signed-off-by: Alex Chiang <[e-mail]>
Signed-off-by: Jesse Barnes <[e-mail]>

drivers/pci/pci-sysfs.c

···
 {
 	int ret = 0;
 	unsigned long val;
-	struct pci_dev *pdev = to_pci_dev(dev);
 
 	if (strict_strtoul(buf, 0, &val) < 0)
 		return -EINVAL;
-
-	if (pci_is_root_bus(pdev->bus))
-		return -EBUSY;
 
 	/* An attribute cannot be unregistered by one of its own methods,
 	 * so we have to use this roundabout approach.