feat(tls): Support runtime ATECC608A I2C address configuration in TLS (IDFGH-16280)

[TheSciBoy]

Description

Includes changes in MQTT and MBED-TLS to support setting the I2C address of a secure element during runtime. This is required for systems where it cannot be determined at compile-time which secure element (ATEC608A) is installed on the hardware, something which may be, for example, configured during production instead.

This way, a new option is added in the configuration to instead of selecting which secure element is used in hardware, a runtime selection item is chosen instead. Checks are added that require the I2C address to be actively set (default is 0, which is not a valid address).

Related

None

Testing

Testing has only been performed on our own proprietary hardware, with the libraries for our own purposes activated. We build locally in a clean docker environment.

Checklist

Before submitting a Pull Request, please ensure the following:

• [ x] 🚨 This PR does not introduce breaking changes.
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• Documentation is updated as needed.
• Tests are updated or added as necessary.
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• [ x] Git history is clean — commits are squashed to the minimum necessary.

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[github-actions]

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[AdityaHPatwardhan]

Hi @TheSciBoy,
Thanks for the PR, Yes, this is indeed helpful. I think one more addition would be to allow dynamically configurable key slot id as well.
We are discussing currently as to how to progress ahead. ( Either to refactor the config to allow more options, or go with the way presented in this PR).
We will take this up soon and update you accordingly.

[TheSciBoy]

Hi @TheSciBoy, Thanks for the PR, Yes, this is indeed helpful. I think one more addition would be to allow dynamically configurable key slot id as well. We are discussing currently as to how to progress ahead. ( Either to refactor the config to allow more options, or go with the way presented in this PR). We will take this up soon and update you accordingly.

Sounds good! I have been busy with other things since I posted the PR and have not had time to dig into the details of contributing yet (such as the CLA), which is why the PR remains in draft. But if you maybe want to refactor this completely, then I will not continue with the PR until you have a decision.