Fix M109 so it won't wait for cooling

Addressing issue #2767

Marlin/Marlin_main.cpp

@@ -4047,7 +4047,7 @@ inline void gcode_M109() {
         }
       #else
         SERIAL_EOL;
-      #endif //TEMP_RESIDENCY_TIME
+      #endif
     }
 
     idle();