Inconsistent API between Maxpooling and Averagepooling

[zhichao-li]

object SpatialMaxPooling extends ModuleSerializable {
  def apply[@specialized(Float, Double) T: ClassTag](
      kW: Int,
      kH: Int,
      dW: Int = 1,
      dH: Int = 1,
      padW: Int = 0,
      padH: Int = 0,
      format: DataFormat = DataFormat.NCHW)

object SpatialAveragePooling {
  def apply[T: ClassTag](
      kW: Int,
      kH: Int,
      dW: Int = 1,
      dH: Int = 1,
      padW: Int = 0,
      padH: Int = 0,
      globalPooling: Boolean = false,
      ceilMode: Boolean = false,
      countIncludePad: Boolean = true,
      divide: Boolean = true,
      format: DataFormat = DataFormat.NCHW)