115200 is a much more sane "default" than 38400.
Instead of a mix of 38400 and 115200, just use 115200 in all places.
There's no reason for modern 32bit cpus to be using such old slow
baudrates.
Tested on f1, f4, l1. Replaced some old f1 code that predated some
library support code for this.
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.
