ESP32: Using RGB_BUILTIN define as pin number in the constructor fail…

…s and resets S2 and S3

I was experimenting with a few different ESP32 boards (C3, S2, S3) and was playing with the on board neopixel and got tired of changing the pin number (C3->8, S2->18, S3->48), and noticed they had a define RGB_BUILTIN and hoped that you could use it in the constructor.

The neopixel failed to work, and on the S2 and S3 it guru-meditated.  Found out they set these values as the pin number plus the count of pins...

So in setPin I checked for this and offset back to the actual pin number.

Adafruit_NeoPixel.cpp

@@ -3045,6 +3045,12 @@ if(is800KHz) {
   @param   p  Arduino pin number (-1 = no pin).
 */
 void Adafruit_NeoPixel::setPin(int16_t p) {
+#if defined(ESP32) && defined(RGB_BUILTIN)
+    if((p == RGB_BUILTIN) && (RGB_BUILTIN > SOC_GPIO_PIN_COUNT)){
+      p -= SOC_GPIO_PIN_COUNT;
+  }
+#endif
+
   if (begun && (pin >= 0))
     pinMode(pin, INPUT); // Disable existing out pin
   pin = p;