LU-8066 obd: collect all resource releasing for obj_type.

LU-8066 obd: collect all resource releasing for obj_type.

Now that obj_type is managed as a kobject, move all
the freeing and deregistering into class_sysfs_release().

Change-Id: I784287ea17e010206b5fa256c7a224d01085be92
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-on: https://review.whamcloud.com/34716
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>