Added getIRQGpio to return DIO0 for Lilygo TLoRa SX1276

variants/lilygo_tlora_v2_1/LilyGoTLoraBoard.h

@@ -21,4 +21,8 @@ public:
 
     return (2 * raw);
   }
+
+  uint32_t getIRQGpio() override {
+    return P_LORA_DIO_0; // default for SX1276
+  }
 };