avformat/utils/av_probe_input_buffer2: fix buffer passed to ffio_rewind_with_probe_data()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 05886c9d4e)

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

libavformat/utils.c

@@ -503,7 +503,7 @@ int av_probe_input_buffer(AVIOContext *pb, AVInputFormat **fmt,
     }
 
     /* rewind. reuse probe buffer to avoid seeking */
-    ret = ffio_rewind_with_probe_data(pb, &buf, pd.buf_size);
+    ret = ffio_rewind_with_probe_data(pb, &buf, buf_offset);
 
     return ret < 0 ? ret : score;
 }