This patch adds XML definitions for guest NUMA specification and contains
routines to parse the same. The guest NUMA specification looks like this:

<cpu>
        ...
        <topology sockets='2' cores='4' threads='2'/>
        <numa>
                <cell cpus='0-7' memory='512000'/>
                <cell cpus='8-15' memory='512000'/>
        </numa>
        ...
</cpu>
Signed-off-by: NBharata B Rao <bharata@linux.vnet.ibm.com>