[Clarification] Provision for AMD HIP backend for MXNet

[sriharikarnam]

In the process of merging HIP Port of MXNet, we are creating a provision for CUDA and HIP backend for mshadow as well. mshadow being sub-module for MXNet.
Please refer ticket apache/mxnet#6257 for disucssion with MXNet team
We are ready with the changes, can we raise a Pull Request, so that the changes can be reviewed and merged to master.

[szha]

This code base has been donated to the Apache MXNet project per #373, and repo is deprecated. Future development and issue tracking should continue in Apache MXNet.