tool/model/analyze_model.py 分析flops文件问题

[maoyj1998]

问题确认 Search before asking

• 我已经查询历史issue(包括open与closed)，没有发现相似的bug。I have searched the open and closed issues and found no similar bug report.

Bug描述 Describe the Bug

在运行tool/model/analyze_model.py出现错误：
AttributeError: 'Config' object has no attribute 'model'

tool/model/analyze_model.py源码中并没有根据model_cfg实例化出一个具体的model，而在'_dynamic_flops'函数中，
代码不断调用model.train(),'model.eval()'等函数

复现环境 Environment

platform: Linux-5.10.16.3-microsoft-standard-WSL2-x86_64-with-glibc2.31
Python: 3.9.0 (default, Nov 15 2020, 14:28:56) [GCC 7.3.0]
Paddle compiled with cuda: False
GCC: gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
PaddleSeg: 2.8.0
PaddlePaddle: 2.4.2
OpenCV: 4.5.5

Bug描述确认 Bug description confirmation

• 我确认已经提供了Bug复现步骤、代码改动说明、以及环境信息，确认问题是可以复现的。I confirm that the bug replication steps, code change instructions, and environment information have been provided, and the problem can be reproduced.

是否愿意提交PR？ Are you willing to submit a PR?

• 我愿意提交PR！I'd like to help by submitting a PR!

[Asthestarsfalll]

这是一个bug，稍后会进行修复，你可以先用更低版本的paddleseg