linux: cve-exclusions: Fix false negatives

linux: cve-exclusions: Fix false negatives

Amend the generate-cve-exclusions.py checking logic in part of the code
responsible for iterating the "affected" defaultStatus part of the JSON
structure in order to mitigate occurrences of false negatives in the
generated output, as well as occurrences of wrong reason for negative
result in case where the reason is actually that the checked kernel
version is in backport fix scope.

In tandem we regenerate the content of cve-exclusion_6.12.inc using
https://github.com/CVEProject/cvelistV5.git repository main branch at
git hash b20d0043711588b6409ae3118bc0510ab888c316 to keep the content
in sync with the script.

Signed-off-by: Niko Mauno <niko.mauno@vaisala.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>