Hi all,

I've updated my USB driver a bit and I hope that I haven't forgotten to
address any of the review comments.

Since I've been testing this on my own STM32F405VG based board that
nobody else has access to I didn't have any good place in Zephyr to show
how to use the USB driver. But I dug around in my boxes of junk and
found two STM32F4 Discovery boards, one with a STM32F407VG on it and
another one with a STM32F401VC. I've added support for all the above
MCUs, and then support for the two Discovery boards. With this in place
I have a patch with my USB driver which then shows how to get a USB
console on both boards.

Some changes to flash_registers.h:

https://gerrit.zephyrproject.org/r/#/c/10612/
https://gerrit.zephyrproject.org/r/#/c/10613/

STM32F401xC, STM32F405xG, STM32F407xG support:

https://gerrit.zephyrproject.org/r/#/c/10306/

Discovery Board definitions:

https://gerrit.zephyrproject.org/r/#/c/10615/
https://gerrit.zephyrproject.org/r/#/c/10616/

Finally the USB stuff:

https://gerrit.zephyrproject.org/r/#/c/10175/
https://gerrit.zephyrproject.org/r/#/c/10176/7

Please take a look if you have the time.

/Christer