s390x/ipl: make s390x ipl device aware of migration

s390x/ipl: make s390x ipl device aware of migration

We have to migrate the reipl parameters, so a reboot on the migrated machine
will behave just like on the origin. Otherwise, the reipl parameters configured
by the guest would be lost.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>