ChibiOS: Add support for stm32F413

[magicrub]

Feature request

Please add support for STM32F413. @bugobliterator has added support on these two branches but they conflict with branch:pr-chibios-update

https://github.com/bugobliterator/ardupilot/tree/pr-f413-nucleo
https://github.com/bugobliterator/ChibiOS-1/tree/pr-f413-dma

Existing problem:
current ChibiOS did not have the STM std lib that had f413 in it. It's a new cpu.
ChibiOS just had a release (May 2018) that included the new STM32 std lib, but no chibiOS support. Then a few (2?) weeks later someone added f413 support. I believe Sid's branch is the chibios/upstream/master that includes those 413 hooks.

So, if we are going to switch over to the "latest ChibiOS", please please please include those few extra commits that allow F413

[tridge]

it would be easy to add F413 if its needed, I don't think we need an issue for it

[peterbarker]

We haven't needed this in 6 years. If it comes up we can deal with it then...