[DOC] update support model download link, test=develop, test=document_fix (#4388)

docs/introduction/support_model_list.md

@@ -22,11 +22,11 @@
 | CV | 检测 | [Faster RCNN](https://paddlepaddle-inference-banchmark.bj.bcebos.com/faster_rcnn.tar) | ARM |
 | CV | 检测 | [Mask RCNN*](https://github.com/PaddlePaddle/PaddleDetection/blob/release/0.4/docs/MODEL_ZOO_cn.md) | ARM |
 | CV | 分割 | [Deeplabv3](https://paddlelite-demo.bj.bcebos.com/models/deeplab_mobilenet_fp32_fluid.tar.gz) | ARM |
-| CV | 分割 | UNet | ARM |
+| CV | 分割 | [UNet](https://paddlelite-demo.bj.bcebos.com/models/Unet.zip) | ARM |
 | CV | 人脸 | [FaceDetection](https://paddlelite-demo.bj.bcebos.com/models/facedetection_fp32_240_430_fluid.tar.gz) | ARM |
 | CV | 人脸 | [FaceBoxes*](https://github.com/PaddlePaddle/PaddleDetection/blob/release/0.4/docs/featured_model/FACE_DETECTION.md#FaceBoxes) | ARM |
 | CV | 人脸 | [BlazeFace*](https://github.com/PaddlePaddle/PaddleDetection/blob/release/0.4/docs/featured_model/FACE_DETECTION.md#BlazeFace) | ARM |
-| CV | 人脸 | MTCNN | ARM |
+| CV | 人脸 | [MTCNN](https://paddlelite-demo.bj.bcebos.com/models/mtcnn.zip) | ARM |
 | CV | OCR | [OCR-Attention](https://paddle-inference-dist.bj.bcebos.com/ocr_attention.tar.gz) | ARM |
 | CV | GAN | [CycleGAN*](https://github.com/PaddlePaddle/models/tree/release/1.7/PaddleCV/gan/cycle_gan) | NPU |
 | NLP | 机器翻译 | [Transformer*](https://github.com/PaddlePaddle/models/tree/release/1.8/PaddleNLP/machine_translation/transformer) | ARM，NPU* |