* - fixed performance_counter for CPU DEX

* made changes to start clock @ the first functor and collected perf_counter @ the exceution of last functor for given kernel execution

* - made changes to have max_pool kernel to have exactly one functor
- assert if functor != num_of_ops

* fixed profiler_counter for TBB execution

* avoid unnecessary calculation to enables<map> value

* Addressed PR comments
-   updated "enables" -> list<functors>