On pseries, core-ids are strongly binded to a node-id by the command
line option. If an user tries to add a CPU to the wrong node, he has
an error but it is not really helpful:

  qemu-system-ppc64 ... -smp 1,maxcpus=64,cores=1,threads=1,sockets=1 \
                        -numa node,nodeid=0 -numa node,nodeid=1 ...

  (qemu) device_add power9_v2.0-spapr-cpu-core,core-id=30,node-id=1
  Error: node-id=1 must match numa node specified with -numa option

This patch improves this error message by giving to the user the good
node-id to use with the core-id he's providing

  Error: invalid node-id, must be 0

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20190529160747.778-1-lvivier@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>