Add information about restoring working IOSes (for HackMii Installer) in a FAQ topic

This question gets asked a lot, so I think it would be a good idea to make a sticky with an answer.

Yeah but the problem is: They dont even read the big read letters on the front page. They wont read a sticky either...

The sticky actually links to FAQ on WiiBrew (originally when I wrote them they mirrored each other) so it only contains core, essential questions. But yeah, I can add this one to it.