board: gw_ventana: enable MV88E61XX DSA support

Add MV88E61XX DSA support:
 - update dt to provide internal MDIO bus and port handles.
   U-Boot requires a more restrictive subset of the dt bindings
   required by Linux for the sake of simplifying code
 - update defconfig to remove old driver and enable new one
 - replace mv88e61xx_hw_reset weak override with board_phy_config support
   for register configuration that is outside the scope of the DSA driver

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
diff --git a/arch/arm/dts/imx6qdl-gw5904.dtsi b/arch/arm/dts/imx6qdl-gw5904.dtsi
index 612b6e0..ea54922 100644
--- a/arch/arm/dts/imx6qdl-gw5904.dtsi
+++ b/arch/arm/dts/imx6qdl-gw5904.dtsi
@@ -212,6 +212,27 @@
 			compatible = "marvell,mv88e6085";
 			reg = <0>;
 
+			mdio {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				sw_phy0: ethernet-phy@0 {
+					reg = <0x0>;
+				};
+
+				sw_phy1: ethernet-phy@1 {
+					reg = <0x1>;
+				};
+
+				sw_phy2: ethernet-phy@2 {
+					reg = <0x2>;
+				};
+
+				sw_phy3: ethernet-phy@3 {
+					reg = <0x3>;
+				};
+			};
+
 			ports {
 				#address-cells = <1>;
 				#size-cells = <0>;
@@ -219,27 +240,40 @@
 				port@0 {
 					reg = <0>;
 					label = "lan4";
+					phy-handle = <&sw_phy0>;
+					phy-mode = "internal";
 				};
 
 				port@1 {
 					reg = <1>;
 					label = "lan3";
+					phy-handle = <&sw_phy1>;
+					phy-mode = "internal";
 				};
 
 				port@2 {
 					reg = <2>;
 					label = "lan2";
+					phy-handle = <&sw_phy2>;
+					phy-mode = "internal";
 				};
 
 				port@3 {
 					reg = <3>;
 					label = "lan1";
+					phy-handle = <&sw_phy3>;
+					phy-mode = "internal";
 				};
 
 				port@5 {
 					reg = <5>;
-					label = "cpu";
 					ethernet = <&fec>;
+					phy-mode = "rgmii-id";
+
+					fixed-link {
+						speed = <1000>;
+						full-duplex;
+					};
 				};
 			};
 		};