configure: AVI demux needs exif

Reviewed-by: Thilo Borgmann <thilo.borgmann@mail.de>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

configure

@@ -2305,7 +2305,7 @@ ac3_demuxer_select="ac3_parser"
 asf_demuxer_select="riffdec"
 asf_muxer_select="riffenc"
 asf_stream_muxer_select="asf_muxer"
-avi_demuxer_select="riffdec"
+avi_demuxer_select="riffdec exif"
 avi_muxer_select="riffenc"
 avisynth_demuxer_deps="avisynth"
 avisynth_demuxer_select="riffdec"