Cleanup warnings in sound_beeper_stm32f30x.c when no beeper is

available.

src/main/drivers/sound_beeper_stm32f30x.c

@@ -21,13 +21,17 @@
 
 #include "platform.h"
 
+#include "build_config.h"
+
 #include "gpio.h"
 
 #include "sound_beeper.h"
 
 void initBeeperHardware(beeperConfig_t *config)
 {
-#ifdef BEEPER
+#ifndef BEEPER
+    UNUSED(config);
+#else
     gpio_config_t gpioConfig = {
         config->gpioPin,
         config->gpioMode,