BSP_IO_Init() function

IO_OK if all initializations are OK. Other value if error.

BSP_IO_Init() is using HAL_Delay() function to ensure that stmpe1600 IO Expander is correctly reset. HAL_Delay() function provides accurate delay (in milliseconds) based on variable incremented in SysTick ISR. This implies that if BSP_IO_Init() is called from a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower) than the peripheral interrupt. Otherwise the caller ISR process will be blocked.