[S390] adapt text to cu3088-removal

cu3088 layer for lcs and ctcm has been removed. Thus the reference
to cu3088 in this text is to be removed as well.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>