s390/appldata: remove power management callbacks

Support for power managemant has been removed from s390 since quite
some time. Therefore remove unused power managemant code from the
appldata device driver.

Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>