Update buzzer to default to 21 if GPIO 32 is not defined

Author: netmindz

usermods/buzzer/buzzer.cpp

@@ -5,16 +5,17 @@
 
 #define USERMOD_ID_BUZZER 900
 #ifndef USERMOD_BUZZER_PIN
+#ifdef GPIO_NUM_32
 #define USERMOD_BUZZER_PIN GPIO_NUM_32
+#else
+#define USERMOD_BUZZER_PIN 21
+#endif
 #endif
 
 /*
  * Usermods allow you to add own functionality to WLED more easily
  * See: https://github.com/wled-dev/WLED/wiki/Add-own-functionality
  * 
- * Using a usermod:
- * 1. Copy the usermod into the sketch folder (same folder as wled00.ino)
- * 2. Register the usermod by adding #include "usermod_filename.h" in the top and registerUsermod(new MyUsermodClass()) in the bottom of usermods_list.cpp
  */
 
 class BuzzerUsermod : public Usermod {