* @brief Changes the mapping of the specified pin.
* @param GPIOx: where x can be (A..K) to select the GPIO peripheral for STM32F405xx/407xx and STM32F415xx/417xx devices
* x can be (A..I) to select the GPIO peripheral for STM32F42xxx/43xxx devices.
* x can be (A, B, C, D and H) to select the GPIO peripheral for STM32F401xx devices.
* @param GPIO_PinSource: specifies the pin for the Alternate function.
* This parameter can be GPIO_PinSourcex where x can be (0..15).
* @param GPIO_AFSelection: selects the pin to used as Alternate function.
* This parameter can be one of the following values:
* @arg GPIO_AF_RTC_50Hz: Connect RTC_50Hz pin to AF0 (default after reset)
* @arg GPIO_AF_MCO: Connect MCO pin (MCO1 and MCO2) to AF0 (default after reset)
* @arg GPIO_AF_TAMPER: Connect TAMPER pins (TAMPER_1 and TAMPER_2) to AF0 (default after reset)
* @arg GPIO_AF_SWJ: Connect SWJ pins (SWD and JTAG)to AF0 (default after reset)
* @arg GPIO_AF_TRACE: Connect TRACE pins to AF0 (default after reset)
* @arg GPIO_AF_TIM1: Connect TIM1 pins to AF1
* @arg GPIO_AF_TIM2: Connect TIM2 pins to AF1
* @arg GPIO_AF_TIM3: Connect TIM3 pins to AF2
* @arg GPIO_AF_TIM4: Connect TIM4 pins to AF2
* @arg GPIO_AF_TIM5: Connect TIM5 pins to AF2