Fix: Cortex-A support

[dragonmux]

Detailed description

In this PR we set out to complete the replacement of the apb_read() and apb_write() functions in the Cortex-A code using the newer cortex_dbg_read32() and cortex_dbg_write32() functions as the former functions make gross assumptions about the state and configuration of the AP that no longer hold.

This had resulted in scan-then-crash issues on targets and would have caused issues on any part that has both a Cortex-M and Cortex-A core on the same Access Port as the Cortex-M code would have caused the same state inconsistency problem.

This also reduces the Flash footprint for the Cortex-A support by ~200 bytes.

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, thanks! :)