aiffenc: set correct number of bits foru8 in aiff

with this change QuickTime is able to play u8 aiff file generated by FFmpeg
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/aiffenc.c

@@ -53,7 +53,6 @@ static int aiff_write_header(AVFormatContext *s)
     ffio_wfourcc(pb, aifc ? "AIFC" : "AIFF");
 
     if (aifc) { // compressed audio
-        enc->bits_per_coded_sample = 16;
         if (!enc->block_align) {
             av_log(s, AV_LOG_ERROR, "block align not set\n");
             return -1;

tests/ref/acodec/adpcm-ima_qt

-23cbae1182e150ebf28e0abfb9cba127 *tests/data/fate/acodec-adpcm-ima_qt.aiff
+44691f14cf5bbef5005df27c692b93ab *tests/data/fate/acodec-adpcm-ima_qt.aiff
 281252 tests/data/fate/acodec-adpcm-ima_qt.aiff
 b0fafd002c38fb70acaddfda1a31ed61 *tests/data/fate/acodec-adpcm-ima_qt.out.wav
 stddev:  904.76 PSNR: 37.20 MAXDIFF:34029 bytes:  1058400/  1058560