bus_remove_device: be more careful about incomplete initialization

Prevent bus_remove_device() from crashing if dev->knode_bus has not been
initialized before it's called.

This can happen if the device_add() ended up breaking out early due to
an error, for example.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/bus.c

@@ -530,6 +530,7 @@ void bus_remove_device(struct device *dev)
 		sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
 				  dev->bus_id);
 		device_remove_attrs(dev->bus, dev);
+		if (klist_node_attached(&dev->knode_bus))
 			klist_del(&dev->knode_bus);
 
 		pr_debug("bus: '%s': remove device %s\n",