[cute] Add constexpr specifier to make_tiled_copy

[tsu-bin]

Suppose I have a small helper function to create a tiled_copy automatically with optimal thread tile layout, and I want to this process happen during compile time, here is an example.

template <int thr_num, int buf_rows, int buf_cols,
    template<class> class CopyOpType, class CopyAsType, class OrigType>
auto constexpr make_tiled_cp()
{
  constexpr auto thr_rows = std::min(thr_num, buf_rows);
  constexpr auto thr_cols = thr_num / thr_rows;

  auto thr_tile = make_layout(
      make_shape(Int<thr_rows>{}, Int<thr_cols>{}), LayoutLeft{});

  return make_tiled_copy(
          Copy_Atom<CopyOpType<CopyAsType>, OrigType>{},
          thr_tile,
          Layout<Shape<Int<buf_rows/thr_rows>, Int<buf_cols/thr_cols>>>{});
}

I call this helper function inside the kernel.

constexpr auto g2s_async_cp_q = make_tiled_cp<k_thr_num, CTA_Q, HEAD_DIM, SM80_CP_ASYNC_CACHEGLOBAL, cute::uint128_t, int8_t>();

But currently make_tiled_copy lacks constexpr specifier, I think it would be helpful to add this.