Fix: CRC32 type error

[dragonmux]

Detailed description

While toying with LTO and doing a BMDA build, GCC warned of a type error in the CRC32 header. On checking it out, the type for the length parameter was indeed mismatched between header and both implementations.

This PR addresses this and does cleanup on the CRC32 implementations to bring them up to standard and make them easier to read and understand. Tested against a LPC4370 on both BMP and using BMDA, this offers no functional change but does fix some undefined behaviour.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native)
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

[esden]

LGTM