dt-bindings: net: Add tx and rx internal delays

tx-internal-delays and rx-internal-delays are a common setting for RGMII
capable devices.

These properties are used when the phy-mode or phy-controller is set to
rgmii-id, rgmii-rxid or rgmii-txid.  These modes indicate to the
controller that the PHY will add the internal delay for the connection.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ethernet-phy.yaml

@@ -162,6 +162,18 @@ properties:
     description:
       Specifies a reference to a node representing a SFP cage.
 
+  rx-internal-delay-ps:
+    description: |
+      RGMII Receive PHY Clock Delay defined in pico seconds.  This is used for
+      PHY's that have configurable RX internal delays.  If this property is
+      present then the PHY applies the RX delay.
+
+  tx-internal-delay-ps:
+    description: |
+      RGMII Transmit PHY Clock Delay defined in pico seconds.  This is used for
+      PHY's that have configurable TX internal delays. If this property is
+      present then the PHY applies the TX delay.
+
 required:
   - reg