Small single parameters.

def mtf_image_transformer_tiny_spatial1d():
  """Small single parameters."""
  hparams = mtf_image_transformer_tiny()
  hparams.num_decoder_layers = 6
  hparams.filter_size = 128
  hparams.block_height = 8
  hparams.block_width = 8
  hparams.attention_type = "local1d_spatial"
  hparams.mesh_shape = ""
  hparams.layout = ""
  return hparams