libxc: rework vnuma bits in setup_guest

libxc: rework vnuma bits in setup_guest

Make the setup process similar to PV counterpart. That is, to allocate a
P2M array that covers the whole memory range and start from there. This
is clearer than using an array with no holes in it.

Also the dummy layout should take MMIO hole into consideration. We might
end up having two vmemranges in the dummy layout.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>