spapr: move cpu_setup after kvmppc_set_papr

This moves the xics_cpu_setup() call after kvmppc_set_papr()
in order to get VCPUs initialized as this is required by upcoming
XICS-KVM.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
