As found in 6f2b39c1be6a8b9531264d92138dc2629d51cfa0, you can't just register a
control callback by itself, you can only register them in the set config
callback, (or, at least, _after_ set config has been done.
This has been compile tested only for the extra examples that were found to
have this failing pattern.
My bad, I'd been testing my header includes against a branch with some
draft unification of the adc code. ADC is one of the remaining major
peripherals that isn't unified neatly.
Replace includes of stm32/YY/xxxx.h with stm32/xxxx.h
Replace stm32/YY/nvic.h with cm3/nvic.h.
In some cases, the include list was resorted alphabetically when it was
complicated and I was reviewing them manually, but most of this was
automatically done.
