Fix STM32H7 RCC clock output

[chris-durand]

Fix STM32H7 RCC clock output and add connect() method for alternate function configuration of clock outputs to RCC driver. Tested in hardware on a STM32H755ZI-Q Nucleo.

I haven't yet added an example because support for STM32H7 dual-core is still work in progress. It will go into #844.

Fixes #852

[chris-durand]

Does anyone have an idea why the Windows hosted examples fail? I have already restarted the job once. This PR only touches platform/clock/stm32/rcc.hpp.in …

[salkinium]

Does anyone have an idea why the Windows hosted examples fail?

I've seen it on other PRs too, I think something changed on their end, maybe we need to upgrade the OS version or something…

[chris-durand]

The Windows unit test executable crashes:

Linking········ scons-release\test.exe
scons: *** [phony_target] Error 3221225477
scons: building terminated because of errors.

[chris-durand]

The windows CI fails on all PRs. The compiler version is exactly the same as on the last runs where the unit tests succeeded. I could also exclude that any changes we made on modm recently cause this. I have just rerun the Windows pipeline for a state that previously was fine but it also fails now.

[salkinium]

Nice!
Do you want this merged now, or is this going into the large PR later?

[chris-durand]

Nice! Do you want this merged now, or is this going into the large PR later?

I'd rather like this to be merged soon. I am working on STM32 camera interface support and need the clock out to supply the camera with a reference clock. I'm currently testing this on a H7 dual-core for which support is also not merged yet. It would certainly make my git workflow easier not having to deal with 3 feature branches at once 😉