Remove double transpose for Conv2DBatchnorm

[jmitrevs]

Description

In the layers.py Conv2DBatchnorm makes a transpose if it is the resource strategy, but only for Vivado and VivadoAccelerator backends. Note that Conv2DBatchnorm inherits from Conv2D, and Conv2D makes the same transpose in:

https://github.com/fastmachinelearning/hls4ml/blob/main/hls4ml/backends/vivado/passes/resource_strategy.py#L29-L32

I think therefore the transpose is doubly-applied. I am therefore removing the backend-specific transpose in the layers.py, which regardless does not belong there.

Type of change

• [x] Bug fix (non-breaking change that fixes an issue)

Tests

I assume there's a Conv2DBatchnorm test that will catch this change, but maybe not.

Test Configuration:

Checklist

• [x] I have read the guidelines for contributing.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have made corresponding changes to the documentation.
• [x] My changes generate no new warnings.
• [x] I have installed and run pre-commit on the files I edited or added.
• [ ] I have added tests that prove my fix is effective or that my feature works.

[jmitrevs]

This was motivated by issue #957