update: check.mk tidy path

```
old : python /home/ymin/share/servo/servo-recrack//src/etc/tidy.py /home/ymin/share/servo/servo-recrack//src
current : python /home/ymin/share/servo/servo-recrack/src/etc/tidy.py /home/ymin/share/servo/servo-recrack/src
```

change // -> /