aasc: return correct buffer size from aasc_decode_frame

Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 0be54ad280)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/aasc.c

@@ -137,7 +137,7 @@ static int aasc_decode_frame(AVCodecContext *avctx,
         return ret;
 
     /* report that the buffer was completely consumed */
-    return buf_size;
+    return avpkt->size;
 }
 
 static av_cold int aasc_decode_end(AVCodecContext *avctx)