There's been a lot of posts on this problem. Use the search entering the word tinnitus and this medical section.
In a mild case, the problem will show up only as a hearing loss around the frequency of the whistle - and this is what will show up on an aviation medical. But believe me, the hearing specialists that deal with pilots, are very used to high tone deafness. It rarely affect the pilot's ability to hear the RT, beacon identifying tones etc..