Update dev_addr coding

[frahlg]

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What does this implement/fix? Explain your changes.

The ABP dev address from TTN needs to be converted from little to big endian. Previous code didn't work. Also updated to use the ustruct and ubinascii libraries.

Does this close any currently open issues?

Any relevant logs, error output, etc?

(If it’s long, please paste to https://gist.github.com and insert the link here)

Any other comments?

Where has this been tested?

• Board type and hardware version:
• os.uname() output:

[frahlg]

The ABP dev address from TTN needs to be converted from little to big endian. Previous code didn't work. Also updated to use the ustruct and ubinascii libraries.

[CLAassistant]

All committers have signed the CLA.

[gijsio]

Hi, Im not experiencing any issues with the current setup, nor did we receive any reports of the functionality not working as is. Therefore, I will close your PR here. Please re-open it if you think differently!

Gijs