Fix Heltec Wifi-LoRa kit pinout (espressif#799)

Based on http://esp32.net/images/Heltec/WIFI-LoRa-32/Heltec_WIFI-LoRa-32_DiagramPinoutFromBottom.jpg

Author: RX14

variants/heltec_wifi_lora_32/pins_arduino.h

@@ -11,7 +11,7 @@
 #define digitalPinToInterrupt(p)    (((p)<40)?(p):-1)
 #define digitalPinHasPWM(p)         (p < 34)
 
-static const uint8_t LED_BUILTIN = 2;
+static const uint8_t LED_BUILTIN = 25;
 #define BUILTIN_LED  LED_BUILTIN // backward compatibility
 
 static const uint8_t KEY_BUILTIN = 0;
@@ -28,11 +28,14 @@ static const uint8_t MISO  = 19;
 static const uint8_t SCK   = 5;
 
 static const uint8_t A0 = 36;
+static const uint8_t A1 = 37;
+static const uint8_t A2 = 38;
 static const uint8_t A3 = 39;
 static const uint8_t A4 = 32;
 static const uint8_t A5 = 33;
 static const uint8_t A6 = 34;
 static const uint8_t A7 = 35;
+
 static const uint8_t A10 = 4;
 static const uint8_t A11 = 0;
 static const uint8_t A12 = 2;
@@ -52,10 +55,10 @@ static const uint8_t T4 = 13;
 static const uint8_t T5 = 12;
 static const uint8_t T6 = 14;
 static const uint8_t T7 = 27;
-static const uint8_t T8 = 33;
-static const uint8_t T9 = 32;
+static const uint8_t T8 = 32;
+static const uint8_t T9 = 33;
 
-static const uint8_t DAC1 = 25;
-static const uint8_t DAC2 = 26;
+static const uint8_t DAC1 = 26;
+static const uint8_t DAC2 = 25;
 
 #endif /* Pins_Arduino_h */