vmm: Don't factorize vhost-user configurations

We want to set different default configurations for vhost-user-net and
vhost-user-blk, which is the reason why the common part corresponding to
the number of queues and the queue size cannot be embedded.

This prepares for the following commit, matching API and CLI behaviors.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/api/openapi/cloud-hypervisor.yaml

@@ -372,41 +372,39 @@ components:
           type: boolean
           default: false
 
-    VhostUserConfig:
+    VhostUserNetConfig:
       required:
       - sock
       - num_queues
       - queue_size
+      - mac
       type: object
       properties:
         sock:
           type: string
         num_queues:
           type: integer
-        queue:size:
+        queue_size:
           type: integer
-
-    VhostUserNetConfig:
-      required:
-      - mac
-      - vu_cfg
-      type: object
-      properties:
         mac:
           type: string
-        vu_cfg:
-          $ref: '#/components/schemas/VhostUserConfig'
 
     VhostUserBlkConfig:
       required:
+      - sock
+      - num_queues
+      - queue_size
       - wce
-      - vu_cfg
       type: object
       properties:
+        sock:
+          type: string
+        num_queues:
+          type: integer
+        queue_size:
+          type: integer
         wce:
           type: boolean
-        vu_cfg:
-          $ref: '#/components/schemas/VhostUserConfig'
 
     VsockConfig:
       required: