dt-bindings: net: make internal-delay-ps based on phy-mode

*-internal-delay-ps properties would be applicable only for RGMII interface
modes.

It is changed as per the request.

Ran dt_binding_check to confirm nothing is broken.

link: https://lore.kernel.org/netdev/d8e5f6a8-a7e1-dabd-f4b4-ea8ea21d0a1d@gmail.com/


Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@microchip.com>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>