qmp: add QMP interface "query-cpu-model-expansion"

qmp: add QMP interface "query-cpu-model-expansion"

Let's provide a standardized interface to expand CPU models. This interface
can be used by tooling to get details about a specific CPU model in a
certain configuration, e.g. about the "host" model.

To take care of all architectures, two detail levels for an expansion
are introduced. Certain architectures might not support all detail levels.
While "full" will expand and indicate all relevant properties/features
of a CPU model, "static" expands to a static base CPU model, that will
never change between QEMU versions and therefore have the same features
when used under different compatibility machines.

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Message-Id: <20160905085244.99980-26-dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>