stm32f4xx gpio: exposed pin/port for GPIO used
stm32f4xx gpio: exposed pin/port for GPIO used

Documentation and refactoring added

RostakaGmfun/theCore,forGGe/theCore,RostakaGmfun/theCore,RostakaGmfun/theCore,RostakaGmfun/theCore,forGGe/theCore,forGGe/theCore,forGGe/theCore