🚸 Allow one servo with cutter on RAMPS

Marlin/src/pins/ramps/pins_RAMPS.h

 // M3/M4/M5 - Spindle/Laser Control
 //
 #if HAS_CUTTER && !defined(SPINDLE_LASER_ENA_PIN)
-  #if !NUM_SERVOS                                 // Use servo connector if possible
+  #if NUM_SERVOS < 2                              // Use servo connector if possible
     #define SPINDLE_LASER_ENA_PIN              4  // Pullup or pulldown!
     #define SPINDLE_LASER_PWM_PIN              6  // Hardware PWM
     #define SPINDLE_DIR_PIN                    5