arm64: dts: rockchip: add cif clk-control pinctrl for rk3399

This enables variant a of the clkout signal for camera applications
and also the cifclkin pinctrl setting.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Tested-by: Sebastian Fricke <sebastian.fricke@posteo.net>
Acked-by: Helen Koike <helen.koike@collabora.com>
Link: https://lore.kernel.org/r/20210210111020.2476369-6-heiko@sntech.de


Signed-off-by: Heiko Stuebner <heiko@sntech.de>