Revert "vhost: introduce new VhostOps vhost_set_config_call"

This reverts commit 88062372.

Fixes: 88062372 ("vhost: introduce new VhostOps vhost_set_config_call")
Cc: "Cindy Lu" <lulu@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

include/hw/virtio/vhost-backend.h

@@ -126,8 +126,6 @@ typedef int (*vhost_get_device_id_op)(struct vhost_dev *dev, uint32_t *dev_id);
 
 typedef bool (*vhost_force_iommu_op)(struct vhost_dev *dev);
 
-typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev,
-                                       int fd);
 typedef struct VhostOps {
     VhostBackendType backend_type;
     vhost_backend_init vhost_backend_init;
@@ -173,7 +171,6 @@ typedef struct VhostOps {
     vhost_vq_get_addr_op  vhost_vq_get_addr;
     vhost_get_device_id_op vhost_get_device_id;
     vhost_force_iommu_op vhost_force_iommu;
-    vhost_set_config_call_op vhost_set_config_call;
 } VhostOps;
 
 int vhost_backend_update_device_iotlb(struct vhost_dev *dev,