dt-bindings: net: add ethernet controller and phy sfp property

Document the missing sfp property for ethernet controllers (which
has existed for some time) which is being extended to ethernet PHYs.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: NRob Herring <robh@kernel.org>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -121,6 +121,11 @@ properties:
       and is useful for determining certain configuration settings
       such as flow control thresholds.
 
+  sfp:
+    $ref: /schemas/types.yaml#definitions/phandle
+    description:
+      Specifies a reference to a node representing a SFP cage.
+
   tx-fifo-depth:
     $ref: /schemas/types.yaml#definitions/uint32
     description:

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

@@ -153,6 +153,11 @@ properties:
       Delay after the reset was deasserted in microseconds. If
       this property is missing the delay will be skipped.
 
+  sfp:
+    $ref: /schemas/types.yaml#definitions/phandle
+    description:
+      Specifies a reference to a node representing a SFP cage.
+
 required:
   - reg