Venus needs firmware that is usually signed with a device-specific key.
There are also devices that might not need it (especially during
bring-up), so let's follow more recent SoCs and disable it by default.
Enable it explicitly for all current devices except msm8916-mtp. That
one has just UART enabled currently so it cannot really benefit from
Venus.
Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>