s390x/kvm: Log unmanageable program interruptions

The kernel only drops to userspace if an endless program interrupt loop
has been detected. Let's print an error message in this case to inform
the user about the crash and stop the affected CPU with a panic event,
just like it is already done for the external interruption loop detection.

Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
