🎨 Misc. spindle/laser adjustments

Marlin/src/HAL/AVR/inc/SanityCheck.h

   #elif NUM_SERVOS > 0 && defined(_useTimer3) && (WITHIN(SPINDLE_LASER_PWM_PIN, 2, 3) || SPINDLE_LASER_PWM_PIN == 5)
     #error "Counter/Timer for SPINDLE_LASER_PWM_PIN is used by the servo system."
   #endif
-#elif defined(SPINDLE_LASER_FREQUENCY)
+#elif SPINDLE_LASER_FREQUENCY
   #error "SPINDLE_LASER_FREQUENCY requires SPINDLE_LASER_USE_PWM."
 #endif
 

Marlin/src/HAL/LPC1768/fast_pwm.cpp

     LPC176x::pwm_write_ratio(pin, invert ? 1.0f - (float)v / v_size : (float)v / v_size);  // map 1-254 onto PWM range
 }
 
-#if NEEDS_HARDWARE_PWM // Specific meta-flag for features that mandate PWM
-
-  void set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
-    LPC176x::pwm_set_frequency(pin, f_desired);
-  }
-
-#endif
+void set_pwm_frequency(const pin_t pin, const uint16_t f_desired) {
+  LPC176x::pwm_set_frequency(pin, f_desired);
+}
 
 #endif // TARGET_LPC1768

Marlin/src/feature/spindle_laser.cpp

     SET_PWM(SPINDLE_LASER_PWM_PIN);
     set_pwm_duty(pin_t(SPINDLE_LASER_PWM_PIN), SPINDLE_LASER_PWM_OFF); // Set to lowest speed
   #endif
-  #if ENABLED(HAL_CAN_SET_PWM_FREQ) && defined(SPINDLE_LASER_FREQUENCY)
+  #if ENABLED(HAL_CAN_SET_PWM_FREQ) && SPINDLE_LASER_FREQUENCY
     set_pwm_frequency(pin_t(SPINDLE_LASER_PWM_PIN), SPINDLE_LASER_FREQUENCY);
     TERN_(MARLIN_DEV_MODE, frequency = SPINDLE_LASER_FREQUENCY);
   #endif
   #if ENABLED(AIR_ASSIST)
     OUT_WRITE(AIR_ASSIST_PIN, !AIR_ASSIST_ACTIVE);                    // Init Air Assist OFF
   #endif
-  #if ENABLED(I2C_AMMETER)
-    ammeter.init();                                                   // Init I2C Ammeter
-  #endif
+  TERN_(I2C_AMMETER, ammeter.init());                                 // Init I2C Ammeter
 }
 
 #if ENABLED(SPINDLE_LASER_USE_PWM)
    * @param ocr Power value
    */
   void SpindleLaser::_set_ocr(const uint8_t ocr) {
-    #if NEEDS_HARDWARE_PWM && SPINDLE_LASER_FREQUENCY
+    #if ENABLED(HAL_CAN_SET_PWM_FREQ) && SPINDLE_LASER_FREQUENCY
       set_pwm_frequency(pin_t(SPINDLE_LASER_PWM_PIN), TERN(MARLIN_DEV_MODE, frequency, SPINDLE_LASER_FREQUENCY));
     #endif
     set_pwm_duty(pin_t(SPINDLE_LASER_PWM_PIN), ocr ^ SPINDLE_LASER_PWM_OFF);

Marlin/src/lcd/menu/menu_spindle_laser.cpp

       ACTION_ITEM(MSG_LASER_FIRE_PULSE, cutter.test_fire_pulse);
     #endif
 
-    #if BOTH(MARLIN_DEV_MODE, HAL_CAN_SET_PWM_FREQ) && defined(SPINDLE_LASER_FREQUENCY)
+    #if BOTH(MARLIN_DEV_MODE, HAL_CAN_SET_PWM_FREQ) && SPINDLE_LASER_FREQUENCY
       EDIT_ITEM_FAST(CUTTER_MENU_FREQUENCY_TYPE, MSG_CUTTER_FREQUENCY, &cutter.frequency, 2000, 80000, cutter.refresh_frequency);
     #endif