Add the function of GPIO initialization
Add the function of GPIO initialization

shengwen1997/stm32_pratice,PUCSIE-embedded-course/stm32f4-examples,PUCSIE-embedded-course/stm32f4-examples,PUCSIE-embedded-course/stm32f4-examples,shengwen1997/stm32_pratice,shengwen1997/stm32_pratice,PUCSIE-embedded-course/stm32f4-examples,shengwen1997/stm32_pratice,PUCSIE-embedded-course/stm32f4-examples,PUCSIE-embedded-course/stm32f4-examples,PUCSIE-embedded-course/stm32f4-examples