virsh: nodedev: ability to filter CCW capabilities

Now that the node_device driver is aware of CCW devices, let's hook up
virsh so that we can filter them properly.

Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Signed-off-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>

docs/formatnode.html.in

@@ -324,6 +324,18 @@
               <code>render</code>.</dd>
             </dl>
           </dd>
+          <dt><code>ccw</code></dt>
+          <dd>Describes a Command Channel Word (CCW) device commonly found on
+          the S390 architecture. Sub-elements include:
+            <dl>
+              <dt><code>cssid</code></dt>
+              <dd>The channel subsystem identifier.</dd>
+              <dt><code>ssid</code></dt>
+              <dd>The subchannel-set identifier.</dd>
+              <dt><code>devno</code></dt>
+              <dd>The device number.</dd>
+            </dl>
+          </dd>
         </dl>
       </dd>
     </dl>