[PATCH] USB: move usb_device_class class devices to be real devices

This moves the usb class devices that control the usbfs nodes to show up
in the proper place in the larger device tree.

No userspace changes is needed, this is compatible due to the symlinks
generated by the driver core.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>