i2c: use open drain outputs.
i2c: use open drain outputs.

Configure the pins as open-drain just in case the code forces them
high although it should be configuring them as inputs to let them float high.

Initialize the pins when the driver is initialized.

Enable the internal pull-ups to prevent them floating too high if not
connected and damaging the circuit.

UncleRus/esp-open-rtos,kanflo/esp-open-rtos,mr-nice/esp-open-rtos,someburner/esp-rtos-tests,SuperHouse/esp-open-rtos,sheinz/esp-open-rtos,ourairquality/esp-open-rtos,kanflo/esp-open-rtos,Zaltora/esp-open-rtos,UncleRus/esp-open-rtos,SuperHouse/esp-open-rtos,chaisme/esp8266_FreeRTOS,someburner/esp-rtos-tests,ourairquality/esp-open-rtos,andree182/esp-open-rtos,ourairquality/esp-open-rtos,Zaltora/esp-open-rtos,ourairquality/esp-open-rtos,someburner/esp-rtos-tests,DCoJA/esp-open-rtos,alainmaes/esp-open-rtos,andree182/esp-open-rtos,kanflo/esp-open-rtos,kanflo/esp-open-rtos,ourairquality/esp-open-rtos,SuperHouse/esp-open-rtos,andree182/esp-open-rtos,chaisme/esp8266_FreeRTOS,ourairquality/esp-open-rtos,bhuvanchandra/esp-open-rtos,urx/esp-open-rtos,UncleRus/esp-open-rtos,urx/esp-open-rtos,urx/esp-open-rtos,kanflo/esp-open-rtos,bhuvanchandra/esp-open-rtos,sheinz/esp-open-rtos,bhuvanchandra/esp-open-rtos,UncleRus/esp-open-rtos,bhuvanchandra/esp-open-rtos,sheinz/esp-open-rtos,mr-nice/esp-open-rtos,SuperHouse/esp-open-rtos,alainmaes/esp-open-rtos,andree182/esp-open-rtos,SuperHouse/esp-open-rtos,alainmaes/esp-open-rtos,Zaltora/esp-open-rtos,UncleRus/esp-open-rtos,urx/esp-open-rtos,someburner/esp-rtos-tests,chaisme/esp8266_FreeRTOS,urx/esp-open-rtos,DCoJA/esp-open-rtos,Zaltora/esp-open-rtos,mr-nice/esp-open-rtos,sheinz/esp-open-rtos,SuperHouse/esp-open-rtos,chaisme/esp8266_FreeRTOS,alainmaes/esp-open-rtos,DCoJA/esp-open-rtos,Zaltora/esp-open-rtos,mr-nice/esp-open-rtos,DCoJA/esp-open-rtos,Zaltora/esp-open-rtos,kanflo/esp-open-rtos,UncleRus/esp-open-rtos,urx/esp-open-rtos