hvf: Introduce hvf_arch_init() callback

We will need to install a migration helper for the ARM hvf backend.
Let's introduce an arch callback for the overall hvf init chain to
do so.

Signed-off-by: Alexander Graf <agraf@csgraf.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20210916155404.86958-4-agraf@csgraf.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

accel/hvf/hvf-accel-ops.c

@@ -324,7 +324,8 @@ static int hvf_accel_init(MachineState *ms)
 
     hvf_state = s;
     memory_listener_register(&hvf_memory_listener, &address_space_memory);
-    return 0;
+
+    return hvf_arch_init();
 }
 
 static void hvf_accel_class_init(ObjectClass *oc, void *data)