Fix memory leak in tone/noTone calls (earlephilhower#125)

Was never deleting the tone object on noTone, so eventually the leaked objects would fill up heap and cause a crash. Fixes earlephilhower#121

Author: earlephilhower

cores/rp2040/Tone.cpp

@@ -95,6 +95,7 @@ void noTone(uint8_t pin) {
  if (entry != _toneMap.end()) {
  pio_sm_set_enabled(entry->second->pio, entry->second->sm, false);
 pio_sm_unclaim(entry->second->pio, entry->second->sm);
+ delete entry->second;
  _toneMap.erase(entry);
  pinMode(pin, OUTPUT);
  digitalWrite(pin, LOW);