The current default is to leave the VDE clock's parent at the default,
which is clk_m. However, that is not a configuration that will allow the
VDE to function. Reparent it to pll_p instead to make sure the hardware
can actually decode video content.

Tested-by: Anton Bambura <jenneron@protonmail.com> # ASUS TF701T
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>