i2s_platform_release_occupation() function

- ESP_OK: Deregister I2S port successfully (i.e. that I2S port can used used by other users after this function returns) - ESP_ERR_INVALID_ARG: Invalid argument, e.g. wrong port_id - ESP_ERR_INVALID_STATE: Specific I2S port is free already

This function will help disable the peripheral APB clock as well.