clk: tegra20: Add DEV1/DEV2 OSC dividers

CDEV1/CDEV2 clocks could have corresponding oscillator clock divider as
a parent. Add these dividers in order to be able to provide that parent
option.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Marcel Ziswiler <marcel@ziswiler.com>
Tested-by: Marcel Ziswiler <marcel@ziswiler.com>
Tested-by: Marc Dietrich <marvin24@gmx.de>
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>