KVM: s390: implement the RI support of guest

This patch adds runtime instrumentation support for KVM guest. We need to
setup a save area for the runtime instrumentation-controls control block(RICCB)
and implement the necessary interfaces to live migrate the guest settings.

We setup the sie control block in a way, that the runtime
instrumentation instructions of a guest are handled by hardware.

We also add a capability KVM_CAP_S390_RI to make this feature opt-in as
it needs migration support.

Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>