Ethernet digitalPinToInterrupt support

Added support for Arduino Ethernet as required in #3929

Author: agdl

variants/ethernet/pins_arduino.h

@@ -58,6 +58,8 @@ static const uint8_t A7 = 21;
 #define digitalPinToPCMSK(p)    (((p) <= 7) ? (&PCMSK2) : (((p) <= 13) ? (&PCMSK0) : (((p) <= 21) ? (&PCMSK1) : ((uint8_t *)0))))
 #define digitalPinToPCMSKbit(p) (((p) <= 7) ? (p) : (((p) <= 13) ? ((p) - 8) : ((p) - 14)))
 
+#define digitalPinToInterrupt(p)  ((p) == 2 ? 0 : ((p) == 3 ? 1 : NOT_AN_INTERRUPT))
+
 #ifdef ARDUINO_MAIN
 
 // On the Arduino board, digital pins are also used