Avoid keeping a local copy of copyleft_compliance.bbclass

Signed-off-by: Christopher Larson <kergoth@gmail.com>
kernel-module-split.bbclass: update to current upstream

Signed-off-by: Christopher Larson <kergoth@gmail.com>
sanity.bbclass: drop, our changes are upstream

Signed-off-by: Christopher Larson <kergoth@gmail.com>