add 24bit support to TTA audio decoder

[ami_stuff]

 http://www.cccp-project.net/beta/test_files/7.1_Fun/8_Channel_ID_TrueTypeAudio.tta

C:\>ffmpeg -i "C:\8_Channel_ID_TrueTypeAudio.tta"
FFmpeg version git-N-29181-ga304071, Copyright (c) 2000-2011 the FFmpeg develope
rs
  built on Apr 18 2011 21:24:03 with gcc 4.5.2
  configuration: --enable-gpl --enable-version3 --enable-runtime-cpudetect --ena
ble-memalign-hack --enable-avisynth --enable-bzlib --enable-frei0r --enable-libo
pencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --
enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enabl
e-libx264 --enable-libxavs --enable-libxvid --enable-zlib --cross-prefix=i686-w6
4-mingw32- --target-os=mingw32 --arch=x86_32 --extra-cflags=-I/home/kyle/softwar
e/ffmpeg/external-libraries/win32/include --extra-ldflags=-L/home/kyle/software/
ffmpeg/external-libraries/win32/lib --pkg-config=pkg-config
  libavutil    50. 40. 1 / 50. 40. 1
  libavcodec   52.120. 0 / 52.120. 0
  libavformat  52.108. 0 / 52.108. 0
  libavdevice  52.  4. 0 / 52.  4. 0
  libavfilter   1. 79. 0 /  1. 79. 0
  libswscale    0. 13. 0 /  0. 13. 0
[tta @ 022721B0] Invalid/unsupported sample format. Please contact the developers.
    Last message repeated 9 times
[tta @ 01CEC000] Could not find codec parameters (Audio: tta, 48000 Hz, 8 channels)
C:\8_Channel_ID_TrueTypeAudio.tta: could not find codec parameters

[cehoyos]

Not related to 8 channels, but 24bit (s->bps == 3).

[cehoyos]

8 bit and 24 bit decoding support was added to tta, the remaining problem is the same as for ticket 96 - as a workaround, it is possible to increase AVCODEC_MAX_AUDIO_FRAME_SIZE inlibavcodec/avcodec.h