sysfs_class: rename object (class -> sysfs_class)
sysfs_class: rename object (class_device -> sysfs_class_device)
sysfs_device: rename object (device -> sysfs_device)
sysfs_driver: rename object (driver -> sysfs_driver)
sysfs_bus: rename object (bus -> sysfs_bus)
sysfs_attribute: rename object (attribute -> sysfs_attribute)
sysfs_bus: change userdata type to non-weak 'generic'
sysfs_class: change userdata type of class and class_device object to 'generic' with no weak references
sysfs_device: change object to use 'generic' userdata type with weak reference
sysfs_driver: change object to use the 'generic' userdata type with no weak reference