Fix build with and without TOUCH_BUTTONS (#14912)

Marlin/src/lcd/ultralcd.cpp

@@ -764,15 +764,14 @@ void MarlinUI::update() {
 
     // If the action button is pressed...
     static bool wait_for_unclick; // = 0
+    #if ENABLED(TOUCH_BUTTONS)
       if (touch_buttons) {
-      if (buttons & EN_C) {
+        if (!wait_for_unclick && (buttons & EN_C)) {    // If not waiting for a debounce release:
-        if (!wait_for_unclick) {                        // If not waiting for a debounce release:
           wait_for_unclick = true;                      //  - Set debounce flag to ignore continous clicks
           lcd_clicked = !wait_for_user && !no_reentry;  //  - Keep the click if not waiting for a user-click
           wait_for_user = false;                        //  - Any click clears wait for user
           quick_feedback();                             //  - Always make a click sound
         }
-      }
         else if (buttons & (EN_A | EN_B)) {             // Ignore the encoder if clicked, to prevent "slippage"
           const millis_t ms = millis();
           if (ELAPSED(ms, next_button_update_ms)) {
@@ -789,7 +788,8 @@ void MarlinUI::update() {
           }
         }
       }
-    else {
+      else
+    #endif //TOUCH_BUTTONS
     //
     // Integrated LCD click handling via button_pressed()
     //
@@ -801,7 +801,6 @@ void MarlinUI::update() {
         quick_feedback();                             //  - Always make a click sound
       }
     }
-    }
     else wait_for_unclick = false;
 
     #if HAS_DIGITAL_BUTTONS && BUTTON_EXISTS(BACK)