s390/hiperdispatch: Decrease steal time threshold

s390/hiperdispatch: Decrease steal time threshold

Higher steal time thresholds favor low utilization scenarios, which is not
the common case for s390. Set steal time threshold to a lower value to
prioritize vertical high and medium CPUs sooner and allow high utilization
scenarios to benefit from it.

Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>