clk: rockchip: make tightly bound armclk child-clocks read-only

Rockchip SoCs contain clocks tightly bound to the armclk, where the best
rate / divider is supplied by the vendor after careful measuring.
Often this ideal rate may be greater than the current rate.

Therefore prevent the ccf from trying to set these dividers itself by
setting them to read-only.

In the case of the rk3066, this also includes the aclk_cpu, which makes it
necessary to also split its direct child-clocks (pclk_cpu, hclk_cpu, ...)
into individual definitions for rk3066 and rk3188.

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