s390/claw: remove "eieio" calls

If the code really depends on ordering it's already racy. The additional
memory barriers (eieio) don't help with that.
If the code is not racy the memory barriers also aren't needed.

In any case, just remove them.

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