spapr: prepare for qdevification of irq Restructure common properties for sPAPR devices so that IRQ definitions can be added in one place. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Cc: Alexander Graf <agraf@suse.de> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Alexander Graf <agraf@suse.de>