'constexpr' => 'const' for PWM_MOTOR_CURRENT

Marlin/stepper.h

@@ -140,7 +140,7 @@ class Stepper {
       #ifndef PWM_MOTOR_CURRENT
         #define PWM_MOTOR_CURRENT DEFAULT_PWM_MOTOR_CURRENT
       #endif
-      static constexpr int motor_current_setting[3] = PWM_MOTOR_CURRENT;
+      static const int motor_current_setting[3] = PWM_MOTOR_CURRENT;
     #endif
 
     //
@@ -384,4 +384,4 @@ class Stepper {
 
 };
 
-#endif // STEPPER_H
+#endif // STEPPER_H