Documentation: devicetree: revise ethernet device-tree binding about TRGMII

add phy-mode "trgmii" to
Documentation/devicetree/bindings/net/ethernet.txt

Cc: devicetree@vger.kernel.org
Reported-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ethernet.txt

@@ -11,8 +11,8 @@ The following properties are common to the Ethernet controllers:
   the maximum frame size (there's contradiction in ePAPR).
 - phy-mode: string, operation mode of the PHY interface; supported values are
   "mii", "gmii", "sgmii", "qsgmii", "tbi", "rev-mii", "rmii", "rgmii", "rgmii-id",
-  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii"; this is now a de-facto
-  standard property;
+  "rgmii-rxid", "rgmii-txid", "rtbi", "smii", "xgmii", "trgmii"; this is now a
+  de-facto standard property;
 - phy-connection-type: the same as "phy-mode" property but described in ePAPR;
 - phy-handle: phandle, specifies a reference to a node representing a PHY
   device; this property is described in ePAPR and so preferred;