arm64: dts: rockchip: add clocks property to cru node rk3368

Add clocks and clock-names because the device has to have
at least one input clock.
Also in case someone wants to add properties that start with
assign-xxx to fix warnings like:
'clocks' is a dependency of 'assigned-clocks'

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20220329180550.31043-2-jbx6244@gmail.com


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