fix(demo): fix compiler warnings regarding the use of LV_UNUSED (#9403)

Signed-off-by: liuhongchao <liuhongchao@xiaomi.com>

demos/benchmark/lv_demo_benchmark.c

@@ -658,8 +658,6 @@ static void load_scene(uint32_t scene)
 
 static void next_scene_timer_cb(lv_timer_t * timer)
 {
-    LV_UNUSED(timer);
-
     scene_act++;
 
     load_scene(scene_act);

examples/others/fragment/lv_example_fragment_2.c

@@ -68,7 +68,6 @@ void lv_example_fragment_2(void)
 
 static void sample_fragment_ctor(lv_fragment_t * self, void * args)
 {
-    LV_UNUSED(args);
     ((sample_fragment_t *) self)->depth = *((int *) args);
     ((sample_fragment_t *) self)->counter = 0;
 }

examples/others/observer/lv_example_observer_6.c

@@ -59,7 +59,6 @@ typedef struct {
 static void my_panel_style_observer_cb(lv_observer_t * observer, lv_subject_t * subject)
 {
     LV_UNUSED(subject);
-    LV_UNUSED(observer);
 
     lv_theme_mode_t m = (lv_theme_mode_t) lv_subject_get_int(&theme_subject);
     lv_panel_styles_t * styles = (lv_panel_styles_t *) lv_observer_get_target(observer);
@@ -129,7 +128,6 @@ typedef struct {
 static void my_button_style_observer_cb(lv_observer_t * observer, lv_subject_t * subject)
 {
     LV_UNUSED(subject);
-    LV_UNUSED(observer);
 
     lv_theme_mode_t m = (lv_theme_mode_t) lv_subject_get_int(&theme_subject);
     lv_button_styles_t * styles = (lv_button_styles_t *) lv_observer_get_target(observer);

examples/widgets/checkbox/lv_example_checkbox_1.c

@@ -5,8 +5,8 @@ static void event_handler(lv_event_t * e)
 {
     lv_event_code_t code = lv_event_get_code(e);
     lv_obj_t * obj = lv_event_get_target_obj(e);
+    LV_UNUSED(obj);
     if(code == LV_EVENT_VALUE_CHANGED) {
-        LV_UNUSED(obj);
         const char * txt = lv_checkbox_get_text(obj);
         const char * state = lv_obj_get_state(obj) & LV_STATE_CHECKED ? "Checked" : "Unchecked";
         LV_UNUSED(txt);

examples/widgets/list/lv_example_list_1.c

@@ -6,8 +6,8 @@ static void event_handler(lv_event_t * e)
 {
     lv_event_code_t code = lv_event_get_code(e);
     lv_obj_t * obj = lv_event_get_target_obj(e);
+    LV_UNUSED(obj);
     if(code == LV_EVENT_CLICKED) {
-        LV_UNUSED(obj);
         LV_LOG_USER("Clicked: %s", lv_list_get_button_text(list1, obj));
     }
 }

examples/widgets/switch/lv_example_switch_1.c

@@ -5,8 +5,8 @@ static void event_handler(lv_event_t * e)
 {
     lv_event_code_t code = lv_event_get_code(e);
     lv_obj_t * obj = lv_event_get_target_obj(e);
+    LV_UNUSED(obj);
     if(code == LV_EVENT_VALUE_CHANGED) {
-        LV_UNUSED(obj);
         LV_LOG_USER("State: %s\n", lv_obj_has_state(obj, LV_STATE_CHECKED) ? "On" : "Off");
     }
 }

examples/widgets/switch/lv_example_switch_2.c

@@ -5,8 +5,8 @@ static void event_handler(lv_event_t * e)
 {
     lv_event_code_t code = lv_event_get_code(e);
     lv_obj_t * obj = lv_event_get_target_obj(e);
+    LV_UNUSED(obj);
     if(code == LV_EVENT_VALUE_CHANGED) {
-        LV_UNUSED(obj);
         LV_LOG_USER("State: %s\n", lv_obj_has_state(obj, LV_STATE_CHECKED) ? "On" : "Off");
     }
 }

src/core/lv_obj_id_builtin.c

@@ -88,7 +88,6 @@ void lv_obj_set_id(lv_obj_t * obj, void * id)
 
 void lv_obj_free_id(lv_obj_t * obj)
 {
-    LV_UNUSED(obj);
     obj->id = NULL;
 }