ipmi auth failure after user name password change

[Jian Zhang]

Hi,

This is a mail that to report an issue that we are facing with the IPMI authentication
after changing the user name and password (I think this is a important issue).

The root cause of this issue lies in the user synchronization mechanism within net-ipmid and ipmid.
The original mechanism determines whether user information needs to be updated based on the
file's modification timestamp.

Since the BMC is typically an embedded system using the jffs2 filesystem, which has a
32-bit timestamp with second-level precision, modifying both the username and password
within the same second can cause the update to fail, resulting in login failures.

The patch[0] below introduces a file watch mechanism to monitor changes to the password file.
When the file is modified, it resets the last update time to ensure that all updates are
correctly reflected in the password map.

[0]: https://gerrit.openbmc.org/q/topic:%22ipmi-user-update%22

Kindly review the patch and test it, Thanks.

Jian.