libxl: disallow memory relocation when vNUMA is enabled

libxl: disallow memory relocation when vNUMA is enabled

Disallow memory relocation when vNUMA is enabled, because relocated
memory ends up off node. Further more, even if we dynamically expand
node coverage in hvmloader, low memory and high memory may reside
in different physical nodes, blindly relocating low memory to high
memory gives us a sub-optimal configuration.

Introduce a function called libxl__vnuma_configured and use it.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>