set cpi.service as enabled in the systemd presets
the cpi.service from the s390utils package replaced an older
init script. Lets enable that by default. The previous init
script was also enabled by deault (e.g. see
https://src.fedoraproject.org/rpms/s390utils/blob/f23/f/cpi.initd )
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>