kdump on s390 uses a load normal reset to bring the system in a defined
state by doing a subsystem reset. The issuing CPUs will have an initial
CPU reset, all other CPUs will have a CPU reset as defined in POP (no
register content will change).

Implement this as architectured.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>