ARM: dts: ixp4xx: Fix up Actiontec MI424WR DTS files

The KS8995 switch was unconditionally wired to EthC (eth1)
on both MI424WR variants, this is wrong: the D revision has
the switch connected to EthB (eth0) so pull this assingment
out of the generic MI424WR DTSI file and make it a property
of the respective variants instead.

Signed-off-by: Linus Walleij <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Krzysztof Kozlowski <[e-mail]>

arch/arm/boot/dts/intel/ixp/intel-ixp42x-actiontec-mi424wr-ac.dts

···
 	model = "Actiontec MI424WR rev A/C";
 	compatible = "actiontec,mi424wr-ac", "intel,ixp42x";
 
+	/* Connect the switch to EthC */
+	spi {
+		ethernet-switch@0 {
+			ethernet-ports {
+				ethernet-port@4 {
+					ethernet = <&ethc>;
+				};
+			};
+		};
+	};
+
 	soc {
 		/* EthB used for WAN */
 		ethernet@c8009000 {

arch/arm/boot/dts/intel/ixp/intel-ixp42x-actiontec-mi424wr-d.dts

···
 	model = "Actiontec MI424WR rev D";
 	compatible = "actiontec,mi424wr-d", "intel,ixp42x";
 
+	/* Connect the switch to EthB */
+	spi {
+		ethernet-switch@0 {
+			ethernet-ports {
+				ethernet-port@4 {
+					ethernet = <&ethb>;
+				};
+			};
+		};
+	};
+
 	soc {
 		/* EthB used for LAN */
 		ethernet@c8009000 {

arch/arm/boot/dts/intel/ixp/intel-ixp42x-actiontec-mi424wr.dtsi

···
 				};
 				ethernet-port@4 {
 					reg = <4>;
-					ethernet = <&ethc>;
 					phy-mode = "mii";
 					fixed-link {
 						speed = <100>;