Remove private declaration

Firmware/temperature.h

@@ -79,10 +79,6 @@ extern int current_voltage_raw_bed;
 extern uint16_t current_voltage_raw_IR;
 #endif //IR_SENSOR_ANALOG
 
-#if defined(CONTROLLERFAN_PIN) && CONTROLLERFAN_PIN > -1
-  extern unsigned char soft_pwm_bed;
-#endif
-
 extern bool bedPWMDisabled;
 
 #ifdef PIDTEMP