clk: rockchip: add dt-binding header for rk3036

Add the dt-bindings header for the rk3036, that gets shared between
the clock controller and the clock references in the dts.

Signed-off-by: Xing Zheng <zhengxing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>