SV2P model for atari with softmax.

def next_frame_sv2p_atari_softmax():
  """SV2P model for atari with softmax."""
  hparams = next_frame_sv2p_atari()
  hparams.bottom = {}
  hparams.loss = {}
  hparams.top = {}
  hparams.internal_loss = True
  return hparams