If I understand correctly, the document has not been revised in 7 years but the content is still good, there is no need to revise the information contained in the document. However, an auditor wants it to be updated. Correct?
I see nothing in 7.5.2, or all of 7.5 period, that requires a document be updated at any specified interval.
Common sense tells us if the process changed but the controlling document did not change, then that is a problem. But why change it for an arbitrary reason like "X amount of time has passed"?
I think your auditor is creating a requirement that does not exist. Tell him/her "show me the specific 'shall' that I am violating".