[PATCH] CLASS: move a "simple" class logic into the class core.

One step on improving the class api so that it can not be used incorrectly.
This also fixes the module owner issue with the dev files that happened when
the devt logic moved to the class core.

Based on a patch originally written by Kay Sievers <kay.sievers@vrfy.org>

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>