[RFC] audit: allow audit_reusename to check kernel path

[Yiwen Gu]

For now, we met a situation where the audit_reusename checking
function returns the same filename structure for files sharing
the same uptr. However, these files are different, and we are trying
to open them in a loop where the names are loaded into the same address.
Therefore, the function returns the same structure for different files.
By the way, may I ask in what situation would the audit_list be kept
across syscalls?