I would rule that it doesn't.

1. Break enchantment isnt on the list.
2. That list includes the spells normally used for curing a permanent, major disability. Feeblemind doesnt have a limit in rounds... the magic effects you, your brain is feebled,.... and that is how you are from then on out. There is no lingering enchantment so to speak.. nothing to be dispelled... You have been permanently munged, much like a level drain. (Note the game mechanic "remembers your normal condition." Otherwise you could feasibly use spells to restore levels you never lost.)