error: static assertion failed: Specified Data Type not supported

**Tensorflow complain

> error: static assertion failed: Specified Data Type not supported

when compiling with BUILD_CUDA_MODULE and BUILD_TENSORFLOW_OPS ON**

**Screenshots**
```
In file included from /home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h:26:0,
from /home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/device_base.h:26,
from /home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/op_kernel.h:27,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/TensorFlowHelper.h:28,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.h:26,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:27:
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/types.h: In instantiation of ‘struct tensorflow::DataTypeToEnum’:
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h:851:33: required from ‘typename tensorflow::TTypes::ConstTensor tensorflow::Tensor::shaped(tensorflow::gtl::ArraySlice) const [with T = long int; long unsigned int NDIMS = 1; typename tensorflow::TTypes::ConstTensor = Eigen::TensorMap, 16, Eigen::MakePointer>; tensorflow::gtl::ArraySlice = absl::lts_2020_02_25::Span]’
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h:544:24: required from ‘typename tensorflow::TTypes::ConstFlat tensorflow::Tensor::flat() const [with T = long int; typename tensorflow::TTypes::ConstFlat = Eigen::TensorMap, 16, Eigen::MakePointer>]’
/media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:60:13: required from ‘void VoxelizeOpKernelCPU::Kernel(tensorflow::OpKernelContext*, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&) [with T = double]’
/media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:82:1: required from here
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/types.h:361:3: error: static assertion failed: Specified Data Type not supported
static_assert(IsValidDataType::value, "Specified Data Type not supported");
^~~~~~~~~~~~~
In file included from /home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/device_base.h:26:0,
from /home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/op_kernel.h:27,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/TensorFlowHelper.h:28,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.h:26,
from /media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:27:
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h: In instantiation of ‘typename tensorflow::TTypes::ConstTensor tensorflow::Tensor::shaped(tensorflow::gtl::ArraySlice) const [with T = long int; long unsigned int NDIMS = 1; typename tensorflow::TTypes::ConstTensor = Eigen::TensorMap, 16, Eigen::MakePointer>; tensorflow::gtl::ArraySlice = absl::lts_2020_02_25::Span]’:
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h:544:24: required from ‘typename tensorflow::TTypes::ConstFlat tensorflow::Tensor::flat() const [with T = long int; typename tensorflow::TTypes::ConstFlat = Eigen::TensorMap, 16, Eigen::MakePointer>]’
/media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:60:13: required from ‘void VoxelizeOpKernelCPU::Kernel(tensorflow::OpKernelContext*, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&, const tensorflow::Tensor&) [with T = double]’
/media/asher/data/pcl_projects/Open3D/cpp/open3d/ml/tensorflow/misc/VoxelizeOpKernel.cpp:82:1: required from here
/home/asher/.conda/envs/open3d/lib/python3.6/site-packages/tensorflow/include/tensorflow/core/framework/tensor.h:851:33: error: ‘v’ is not a member of ‘tensorflow::DataTypeToEnum’
CheckType(DataTypeToEnum::v());
~~~~~~~~~~~~~~~~~~~~^~
cpp/open3d/ml/tensorflow/CMakeFiles/open3d_tf_ops.dir/build.make:461: recipe for target 'cpp/open3d/ml/tensorflow/CMakeFiles/open3d_tf_ops.dir/misc/VoxelizeOpKernel.cpp.o' failed
make[3]: *** [cpp/open3d/ml/tensorflow/CMakeFiles/open3d_tf_ops.dir/misc/VoxelizeOpKernel.cpp.o] Error 1
```

**Environment (please complete the following information):**
- Operating system: Ubuntu 18.04
- Python version: Python 3.6
- Open3D version:　0.13.0
- How did you install Open3D?: build from source
- Compiler version (if built from source): gcc 7.5, clang 7.0