vhost: remove unnecessary forward declarations in vhost.h

Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.h

@@ -12,8 +12,6 @@
 #include <linux/virtio_ring.h>
 #include <linux/atomic.h>
 
-struct vhost_device;
-
 struct vhost_work;
 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
 
@@ -54,8 +52,6 @@ struct vhost_log {
 	u64 len;
 };
 
-struct vhost_virtqueue;
-
 /* The virtqueue structure describes a queue attached to a device. */
 struct vhost_virtqueue {
 	struct vhost_dev *dev;