CDROM: Ignore sectors with channel number 255 (#195)

This was inspired by the fix in Duckstation :
https://github.com/stenzek/duckstation/commit/0710e3b6d384526ed939f742f8f657623bb354bb

Some games have junk audio sectors with a channel number of 255.
If these are not skipped, then they will play wrong file.

This was tested on "Blue's Clues : Blue's Big Musical" and
it fixed the missing audio there.

Taxi 2 is also said to be affected by this.