Presumably code that attempted to toggle a led, but it wasn't setup, and it's
not in any other examples. Kill it for now.
Reported-by: stefanct on irc.
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.