Mxnet parser for Qnn dialect (#4714)

Mxnet parser for Qnn dialect (#4714)

* - Additional util methods needed for mxnet frontend for qnn dialect.

* - Fixing call to quantize.

* [QNN] MxNet-MKLDNN parser support for QNN

* [QNN] Relax conv check.

* - Merge from origin

* [QNN] Channel wise changes

* [QNN] Dense changes

* Dense fix for QNN ops.

* - Removed non-mkl code from utils.

- Small refactoring

- Remove "with_sum" from conv

- Simplified code

* - Fixing ring buffer name.

* - Fixing pylint issues.

* - Fixing lint
- Removing redundant commented code.

* - Adding test cases
- Removing unused methods.

* [WIP] end to end test case for mxnet qnn parser

* Changes to parse large CV models.

* Pylint issues.

* Fix Conv2D with sum and quantized pooling.

* Reverting the changes made for mxnet-mkldnn test cases. Because of #4753, mxnet could not be updated to mxnet-mkldnn.

Co-authored-by: Animesh Jain <anijain@umich.edu>