dt-bindings: clocks: add rk3288w variant compatible

Add the possible compatible "rockchip,rk3288w-cru" that handles
the difference between the rk3288 and the new revision rk3288w.

This compatible will be added by bootloaders.

Signed-off-by: Mylène Josserand <mylene.josserand@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200602080644.11333-3-mylene.josserand@collabora.com


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