Changelog:
- Hardened the libjpeg API against hypothetical calling applications that may
erroneously change the value of the 'data_precision' field in
'jpeg_compress_struct' or 'jpeg_decompress_struct' after calling
'jpeg_start_compress()' or 'jpeg_start_decompress()'.
Signed-off-by: Wang Mingyu <wangmy@fujitsu.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>