VIDEO: Wrap 8-bit smacker audio properly

The accumulator 'bases' is 16-bit but when used in 8-bit audio we need to
wrap as if 'bases' is 8-bit. Clipping on output is no longer required.

This fixes noise in The Neverhood's in-game "making of" videos,
particularly the section called "Construction, powertools & painting",
hash 0x21080009.

The intro video in The Neverhood is 16-bit audio and was not affected by
this bug. No other videos or games have been tested.
Merge pull request #336 from madmoose/smacker-8-bit-audio-fix

VIDEO: Wrap 8-bit smacker audio properly