tiff: mark CVE-2022-1622 and CVE-2022-1623 as invalid

These issues only affect libtiff post-4.3.0 but before 4.4.0, caused by
3079627e and fixed by b4e79bfa.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>