drivers: tcpc: add FUSB302B TCPC driver

[ottojo]

This adds a driver for the onsemi FUSB302B USB Type-C controller IC, implementing a TCPC and VBUS-sensor.
This IC is present on the otterpill board introduced in #62830.

The driver is pretty minimal, intended to only implement the minimal subset of TCPC functionality required for requesting a higher voltage than 5V from a source.

For testing simplicity, this PR currently contains the otterpill board definition from #62830 as well.

[raveslave]

curious if anyone is using this?

[ottojo]

To update the current status on this: The driver does work in that it can successfully request a specific voltage from a PD PSU, i didnt test any functionality beyond that.
There are some problems with reliability though, IIRC the continuous measurement of CC states seemed to interrupt communication with the PSU at times (since it meant connecting the measurement block in the chip to each CC one after another). It might be worth using the interrupt functionality of the FUSB302 and just storing the current state in the driver, instead of querying the chip often. (the interrupt functionality is not used at all in this driver currently)

That said, I was just working on that out of personal curiosity, and having the proper devboard laying around. I'm not planning on working on this more in the short term. The latest version of this is found in an OOT module, which i made for easier experimenting: https://github.com/ottojo/zephyr_fusb302b
If anyone wants to make a proper FUSB302 zephyr driver, feel free to use this as a starting point, but also know that there is a linux driver out there for example, which surely is a lot more mature and actually battle tested.