hw/cxl/events: Mark cxl-add-dynamic-capacity and cxl-release-dynamic-capcity unstable

hw/cxl/events: Mark cxl-add-dynamic-capacity and cxl-release-dynamic-capcity unstable

Markus suggested that we make the unstable. I don't expect these
interfaces to change because of their tight coupling to the Compute
Express Link (CXL) Specification, Revision 3.1 Fabric Management API
definitions which can only be extended in backwards compatible way.
However, there seems little disadvantage in taking a cautious path
for now and marking them as unstable interfaces.

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20240625170805.359278-3-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>