drivers: dac: Add support for Microchip MCP48XX devices

[emz229]

This driver covers the MCP4802, MCP4812, and MCP4822 DACs.

[github-actions]

Hello @emz229, and thank you very much for your first pull request to the Zephyr project!
Our Continuous Integration pipeline will execute a series of checks on your Pull Request commit messages and code, and you are expected to address any failures by updating the PR. Please take a look at our commit message guidelines to find out how to format your commit messages, and at our contribution workflow to understand how to update your Pull Request. If you haven't already, please make sure to review the project's Contributor Expectations and update (by amending and force-pushing the commits) your pull request if necessary.
If you are stuck or need help please join us on Discord and ask your question there. Additionally, you can escalate the review when applicable. 😊

[martinjaeger]

Thanks @emz229 for your contribution.

Generally the PR looks good. However, I need to have some more thoughts regarding the latch pin for synchronization. Given that there are more chips with such a pin (e.g. TI dacx3608) we should find a generic solution for that and include the functionality into the actual DAC API.

Please note that we are currently still in feature freeze for Zephyr v3.7 and the PR can only be merged after that. I will come back with a suggestion regarding the latch pin ASAP.

[MaureenHelm]

@emz229 do you plan to come back to this PR?

[emz229]

@MaureenHelm I am monitoring the thread where it is being discussed by several maintainers. See https://github.com/zephyrproject-rtos/zephyr/issues/73090

[github-actions]

This pull request has been marked as stale because it has been open (more than) 60 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 14 days. Note, that you can always re-open a closed pull request at any time.