dt-bindings: soc: rockchip: grf: add rockchip,rk3128-grf

Add rockchip,rk3128-grf compatible string.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/fddc23ff-0c87-4998-1bdf-4dbfa4c74046@gmail.com


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