bogus wakes on TBEAMS because the USB->SERIAL chip pulls the RX input
to ground. This feature is no longer needed because in !isRouter
nodes we force the node to never sleep anyways when on USB power.
// this doesn't work on TBEAMs when the USB is depowered (causes bogus interrupts)
// So we disable this "wake on serial" feature - because now when a TBEAM (only) has power connected it
// never tries to go to sleep if the user is using the API
// gpio_wakeup_enable((gpio_num_t)SERIAL0_RX_GPIO, GPIO_INTR_LOW_LEVEL);
