[BE] Fix Convolution.cpp build warnings (#60463)
Summary:
Use `c10::irange` and `auto` to get rid of narrowing cast and signed-unsigned compilation warnings
Pull Request resolved: https://github.com/pytorch/pytorch/pull/60463
Reviewed By: samestep
Differential Revision: D29300415
Pulled By: malfet
fbshipit-source-id: 4d7f519e2e3ebaa754364f60af762658c1b4a62e
