spapr: Add H-Call H_HOME_NODE_ASSOCIATIVITY

spapr: Add H-Call H_HOME_NODE_ASSOCIATIVITY

H_HOME_NODE_ASSOCIATIVITY H-Call returns the associativity domain
designation associated with the identifier input parameter

This fixes a crash when we try to hotplug a CPU in memory-less and
CPU-less numa node. In this case, the kernel tries to online the
node, but without the information provided by this h-call, the node id,
it cannot and the CPU is started while the node is not onlined.

It also removes the warning message from the kernel:
  VPHN is not supported. Disabling polling..

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>