fix(cpus/denver): use CPU_NO_EXTRA3_FUNC for all variants

Denver CPUs use the same workaround for CVE-2017-5715 and CVE-2022-23960
vulnerabilities. The workaround for CVE-2017-5715 is always enabled, so
all Denver variants use CPU_NO_EXTRA3_FUNC as a placeholder for the
mitigation for CVE-2022-23960. This patch implements the approach.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Change-Id: I0863541ce19b6b3b6d1b2f901d3fb6a77f315189