修复 当AD盒的systick 比电脑要慢5秒，调整到systick 为当前时间

Project.FLY.FlyADBase/FlyADBase/FlyAD7.cs

@@ -590,7 +590,12 @@ namespace FlyADBase
 
                     systick_1st = systick;
                     dt_1st = dt;
-
+                    if (Math.Abs((DateTime.Now-dt).TotalSeconds) > 5000)//滞后5s，异常
+                    {
+                        //修正
+                        dt = DateTime.Now;
+                        dt_1st = dt;
+                    }
                     return dt;
                 }