vhost: Remove comments for hdr in vhost.h

It is supposed to be removed when hdr is moved into vhost_net_virtqueue.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.h

@@ -99,9 +99,6 @@ struct vhost_virtqueue {
 	u64 log_addr;
 
 	struct iovec iov[UIO_MAXIOV];
-	/* hdr is used to store the virtio header.
-	 * Since each iovec has >= 1 byte length, we never need more than
-	 * header length entries to store the header. */
 	struct iovec *indirect;
 	struct vring_used_elem *heads;
 	/* We use a kind of RCU to access private pointer.