s390/zcrypt: Introduce workload balancing

Crypto requests are very different in complexity and thus runtime.
Also various crypto adapters are differ with regard to the execution
time. Crypto requests can be balanced much better when the request
type and eligible crypto adapters are rated in a more precise
granularity. Therefore, request weights and adapter speed rates for
dedicated requests will be introduced.

Signed-off-by: Ingo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>