Fix STM32F7 STEPPER_ENABLE_PIN

Marlin/src/HAL/HAL_STM32_F4_F7/STM32F7/HAL_timers_STM32F7.cpp

       timerConfig[0].IRQ_Id = TIM5_IRQn;
       timerConfig[0].callback = (uint32_t)TC5_Handler;
       HAL_NVIC_SetPriority(timerConfig[0].IRQ_Id, 1, 0);
-      SET_OUTPUT(STEPPER_ENABLE_PIN);
-      WRITE(STEPPER_ENABLE_PIN);
+      #if PIN_EXISTS(STEPPER_ENABLE)
+        OUT_WRITE(STEPPER_ENABLE_PIN, HIGH);
+      #endif
       break;
     case TEMP_TIMER_NUM:
       //TEMP TIMER TIM7 // any available 16bit Timer (1 already used for PWM)

Marlin/src/HAL/HAL_STM32_F4_F7/STM32F7/TMC2660.cpp

   pinMode(step_pin, OUTPUT);
   pinMode(dir_pin, OUTPUT);
   pinMode(cs_pin, OUTPUT);
-  //SET_OUTPUT(STEPPER_ENABLE_PIN);
   extDigitalWrite(step_pin, LOW);
   extDigitalWrite(dir_pin, LOW);
   extDigitalWrite(cs_pin, HIGH);