s390/ap: remove power management code from ap bus and drivers

The s390 power management support has been removed. So the
api registration and the suspend and resume callbacks and
all the code related to this for the ap bus and the ap drivers
is removed with this patch.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>