remove unneeded buf_size check (see AVPROBE_PADDING_SIZE)

Originally committed as revision 10060 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/raw.c

@@ -409,9 +409,6 @@ static int ac3_probe(AVProbeData *p)
     uint8_t *buf, *buf2, *end;
     AC3HeaderInfo hdr;
 
-    if(p->buf_size < 7)
-        return 0;
-
     max_frames = 0;
     buf = p->buf;
     end = buf + p->buf_size;