fix topi c++ conv2d_nchw lambda expr issue (#3570)

topi/include/topi/nn.h

@@ -268,7 +268,7 @@ inline tvm::Tensor conv2d_nchw(const tvm::Tensor& I,
                : pad(I, {tvm::Expr(0), tvm::Expr(0), pad_h, pad_w});
   auto l = [&](tvm::Var b, tvm::Var o, tvm::Var h, tvm::Var w) {
     return tvm::sum(
-        T(b, i, stride_h * h + kh, stride_w * w + kw) * W(i, o, kh, kw),
+        T(b, i, stride_h * h + kh, stride_w * w + kw) * W(o, i, kh, kw),
         {i, kh, kw});
   };
   return tvm::compute(output_shape, l, name, tag);