alter path: for linux mkdir, if the folder has been existed in /compat/linux, return EEXIST directly

[weike.chen_dell.com]

Summary

Linux applications calls 'mkdir' to create folder, if it is existed in /compat/linux, the correct implementation creates it in '/'. This behavior causes the failure for the Linux applications use 'mkdir' to check if the folder is existed or not, but have no permission to create folders in '/'.

[weike.chen_dell.com]

Hi team,
Any feedbacks for this fix?