ARM: dts: rockchip: add clocks property to cru node rk3288

Add clocks property to rk3288 cru node 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/20220329113657.4567-2-jbx6244@gmail.com


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