Take the size of the audio data into account when checking for the loop ...

...address.  Fixes the static audio in the FMV of Megaman X Collection, Pac man World, off pitched instruments in Skies of Arcadia and audio desync in the Taiko no Tatsujin series.

Fixes:
issue 7154
issue 7222
issue 7280
issue 7457
Make that =2, =2, =1 instead and -1 the value when checking for the loop. This makes it more clear that it maps to the sample size in bytes (for PCM16 and PCM8 - the "block" size for ADPCM).