dt-bindings: phy: add compatible for rk356x to rockchip-inno-csi-dphy

The driver for the Innosilicon MIPI CSI DPHY is compatible with the variant
in the Rockchip RK356x SoCs. Add the compatible string to the binding.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220720091527.1270365-2-michael.riesch@wolfvision.net


Signed-off-by: Vinod Koul <vkoul@kernel.org>