CC3200使用MQTT的SSL加密证书可用日期修改

1. 在使用CC3200进行SSL加密的时候，需要证书，但是证书有一个截止日期，如果当前CC3200没有设置这个日期，那么证书通信会失败，需要添加代码

int setDeviceTime() {  

  SlDateTime_t dateTime= {};
  dateTime.sl_tm_day =   (_u32);          // Day of month (DD format) range 1-31
  dateTime.sl_tm_mon =   (_u32);           // Month (MM format) in the range of 1-12
  dateTime.sl_tm_year =  (_u32);        // Year (YYYY format)
  dateTime.sl_tm_hour =  (_u32);          // Hours in the range of 0-23
  dateTime.sl_tm_min =   (_u32);          // Minutes in the range of 0-59
  dateTime.sl_tm_sec =   (_u32);          // Seconds in the range of  0-59
  sl_DevSet(SL_DEVICE_GENERAL_CONFIGURATION,
            SL_DEVICE_GENERAL_CONFIGURATION_DATE_TIME,
            sizeof(SlDateTime_t),
            (_u8 *)(&dateTime));
}