phy: dt-bindings: cdns,dphy: add power-domains property

This property is needed on TI platforms to enable the PD of the DPHY
before it can be used.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rob Herring <robh@kernel.org>

Link: https://lore.kernel.org/r/20220301111621.2992275-4-p.yadav@ti.com


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