clk: rockchip: switch to using the new cpuclk type for armclk

This adds the necessary soc-specific divider values and switches the armclk
to use the newly introduced cpuclk type.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>