phy: dt-bindings: cdns,dphy: Add compatible for dphy on j721e

Add compatible to support dphy tx on j721e

Signed-off-by: Rahul T R <r-ravikumar@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220623125433.18467-2-r-ravikumar@ti.com


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