add pinmode initialization in hal_interrupt_init()

Pinmode initialization is missing in hal_interrupt_init().
Without the interrupt driven timestamping mode does not work (tested on ESP32 hardware).
Added just this one extra line and it worked! :-)

Author: cyberman54

src/hal/hal.cpp

@@ -130,6 +130,7 @@ static void hal_interrupt_init() {
       if (plmic_pins->dio[i] == LMIC_UNUSED_PIN)
           continue;
 
+      pinMode(plmic_pins->dio[i], INPUT);
       attachInterrupt(digitalPinToInterrupt(plmic_pins->dio[i]), interrupt_fns[i], RISING);
   }
 }