linux-yocto: tweak cve exclusions files

linux-yocto: tweak cve exclusions files

-tiny and -rt were updated to a 6.12 specific inclusion, but
the -standard kernel was missed.

This commit also creates a 6.12 exclusion file, that is populated
with the last updates for the 6.10 kernel. Although it is no
longer updated automatically, that may change in the future and
it still provides value as a place to manually add CVE exclusions.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>