s390x/kvm: disable cpu model for the 2.7 machine

cpu model was merged with 2.8, it is wrong to abuse ri_allowed which
was enabled with 2.7.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index a0c1fc8..6ecae00 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -36,9 +36,12 @@
 
     /*< public >*/
     bool ri_allowed;
+    bool cpu_model_allowed;
 } S390CcwMachineClass;
 
 /* runtime-instrumentation allowed by the machine */
 bool ri_allowed(void);
+/* cpu model allowed by the machine */
+bool cpu_model_allowed(void);
 
 #endif