make compatible with Nano ESP32 platform

Author: Richard Unger

src/drivers/hardware_specific/generic_mcu.cpp

@@ -1,7 +1,8 @@
+
 #include "../hardware_api.h"
 
 // if the mcu doen't have defiend analogWrite
-#if defined(ESP_H) && defined(ARDUINO_ARCH_ESP32)
+#if defined(ESP_H) && defined(ARDUINO_ARCH_ESP32) && !defined(analogWrite)
   __attribute__((weak)) void analogWrite(uint8_t pin, int value){ };
 #endif