The STM32F3 requires a dedicated digital signal to emulate a disconnect
event by pulling D+ down via a 1.5 kOhm resistor. Some boards, such as
the OLIMEXINO-STM32F3, do not directly connect a GPIO but place a
transistor in between. Depending on the exact implementation, the logic
level may end up being inverted compared to directly connecting a
GPIO.
This adds a flag member to the `stm32_usbdev_fs_config_t` and a new flag
to indicate inverted logic. In addition the members in the struct are
sorted by alignment, as this is a foolproof algorithm to prevent wasting
memory on unneeded padding.
Finally, the USB driver is adapted to honor the flag.
Co-authored-by: crasbe <crasbe@gmail.com>
