Tiny hparams suitable for CIFAR/etc.

def revnet_110_cifar():
  """Tiny hparams suitable for CIFAR/etc."""
  hparams = revnet_cifar_base()
  hparams.bottleneck = False
  hparams.num_channels = [16, 32, 64]
  hparams.num_layers_per_block = [8, 8, 8]
  return hparams