[S390] cmm: add missing __init/__exit annotations

Add missing __init and __exit annoations for module init and exit
functions. This will save us huge amounts of memory... sort of.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>