s390x/tcg: implement Interlocked-Access Facility 2

With this facility, OI/OIY, NI/NIY and XI/XIY are atomic. All operate on
one byte (MO_UB). Emulate old behavior.

Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20171208160207.26494-8-david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
3 files changed