tiff: fix CVE-2025-8534

tiff: fix CVE-2025-8534

A vulnerability classified as problematic was found in libtiff
4.6.0. This vulnerability affects the function PS_Lvl2page of
the file tools/tiff2ps.c of the component tiff2ps. The
manipulation leads to null pointer dereference. It is possible
to launch the attack on the local host. The complexity of an
attack is rather high. The exploitation appears to be difficult.
The exploit has been disclosed to the public and may be used.
The name of the patch is 6ba36f159fd396ad11bf6b7874554197736ecc8b.
It is recommended to apply a patch to fix this issue. One of the
maintainers explains, that "[t]his error only occurs if
DEFER_STRILE_LOAD (defer-strile-load:BOOL=ON) or TIFFOpen( .. "rD")
option is used."

Reference:
https://nvd.nist.gov/vuln/detail/CVE-2025-8534

Upstream patch:
https://gitlab.com/libtiff/libtiff/-/commit/6ba36f159fd396ad11bf6b7874554197736ecc8b

Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>