fpcalc: Fix FFmpeg SAMPLE_FMT_S16 version check
fpcalc: Fix FFmpeg SAMPLE_FMT_S16 version check

This change was introduced in avcodec.h version 52,94,1; see ffmpeg
commit 262d1c5d2206467809fd81d841d09ad70cc8ba13

Fixes build on Ubuntu 10.10 (libavcodec 0.6, avcodec.h version 52,72,2)

capcomvertigo/chromaprint,lalinsky/chromaprint,vonwenm/chromaprint,capcomvertigo/chromaprint,vonwenm/chromaprint,lalinsky/chromaprint