Cleaning up tuning mxnet for performance (#6320)
Cleaning up tuning mxnet for performance (#6320)

* Cleaning up tuning mxnet for performance

* Fixed review comments

* Fixed review comments by Madan

Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet