Followup for BTN_ENC_EN

Marlin/src/lcd/marlinui.cpp

   millis_t MarlinUI::return_to_status_ms = 0;
 #endif
 
+inline bool can_encode() {
+  #if BUTTON_EXISTS(ENC_EN)
+    return !BUTTON_PRESSED(ENC_EN);  // Update position only when ENC_EN is HIGH
+  #else
+    return true;
+  #endif
+}
+
 void MarlinUI::update() {
 
   static uint16_t max_display_update_time = 0;
 
           #endif // ENCODER_RATE_MULTIPLIER
 
-          // Update position only when ENC_EN is HIGH
-          if (TERN1(BTN_ENC_EN, !BUTTON_PRESSED(ENC_EN)))
-            encoderPosition += (encoderDiff * encoderMultiplier) / epps;
+          if (can_encode()) encoderPosition += (encoderDiff * encoderMultiplier) / epps;
 
           encoderDiff = 0;
         }
             if (BUTTON_PRESSED(EN2)) newbutton |= EN_B;
           #endif
           #if BUTTON_EXISTS(ENC)
-            // Update button only when ENC_EN is HIGH
-            if (TERN1(BTN_ENC_EN, !BUTTON_PRESSED(ENC_EN)) && BUTTON_PRESSED(ENC)) newbutton |= EN_C;
+            if (can_encode() && BUTTON_PRESSED(ENC)) newbutton |= EN_C;
           #endif
           #if BUTTON_EXISTS(BACK)
             if (BUTTON_PRESSED(BACK)) newbutton |= EN_D;