Currently VDE clock rate is determined by clock config left from
bootloader, let's not rely on it and explicitly specify the clock
rate in the CCF driver.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com>