fix(vg_lite): fix build break after LV_USE_VECTOR_GRAPHIC is turned off (#8912)

Signed-off-by: pengyiqiang <pengyiqiang@xiaomi.com>
Co-authored-by: pengyiqiang <pengyiqiang@xiaomi.com>

src/draw/vg_lite/lv_draw_vg_lite.c

@@ -310,6 +310,7 @@ static void draw_event_cb(lv_event_t * e)
 
     switch(code) {
         case LV_EVENT_CANCEL: {
+#if LV_USE_VECTOR_GRAPHIC
                 /**
                  * Because VG-Lite will deinitialize the context (including the GPU independent heap)
                  * before the GPU goes to sleep, it is necessary to first discard and dereference
@@ -319,6 +320,7 @@ static void draw_event_cb(lv_event_t * e)
                 lv_cache_drop_all(lv_vg_lite_grad_ctx_get_cache(unit->grad_ctx), NULL);
                 lv_cache_drop_all(unit->stroke_cache, NULL);
                 LV_LOG_INFO("dropt all cache");
+#endif
             }
             break;
         default: