The method scale_shift_nchw in C should add shift from the values of channel

[tobegit3hub]

It is a little confused for me when reading the source code of https://github.com/apache/incubator-tvm/blob/master/topi/include/topi/nn/mapping.h#L51 . The scale_shift_nchw and scale_shift_nhwc should apply scale and shift from the values of channel. There is another implementation in Python topi which seems to be right in https://github.com/apache/incubator-tvm/blob/master/topi/python/topi/nn/mapping.py#L44 .

Should we change the implementation of scale_shift_nchw to this?

inline Tensor scale_shift_nchw(const Tensor& x, const Tensor& scale, const Tensor& shift,
                               std::string name = "ScaleShift", std::string tag = kBroadcast) {
  return tvm::te::compute(
      x->shape, [&](Var b, Var c, Var h, Var w) { return x(b, c, h, w) * scale(c) + shift(c); },
      name, tag);
}