esp32: gpio_make_output needs to select mux configuration

[jonhnet]

Out of the box, I can't use rulos' gpio_make_output to get output out of pins 12, 13, 14 on esp32. That's evidently because they're configured to be attached to the JTAG unit at boot:

https://www.esp32.com/viewtopic.php?t=2687

This extra call solved the problem for me:

  PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[13], PIN_FUNC_GPIO);
  gpio_make_output(14);

Should we do this for every call to gpio_make_output? Should we use that macro layer, or dig in a layer? The current code in esp32/core/hardware.h doesn't use similar-looking macros to configure the output enable.