lantiq: VGV7519 - get mac address from board_config partition

Use the mac address stored in the board_config partition instead of a
static one.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/lantiq/dts/VGV7519.dtsi

@@ -226,7 +226,7 @@
 		#address-cells = <1>;
 		#size-cells = <0>;
 		reg = <0>;
-		mac-address = [ 00 11 22 33 44 55 ];
+		mtd-mac-address = <&boardconfig 0x16>;
 		lantiq,switch;
 
 		ethernet@0 {
@@ -260,7 +260,8 @@
 		#address-cells = <1>;
 		#size-cells = <0>;
 		reg = <1>;
-		mac-address = [ 00 11 22 33 44 56 ];
+		mtd-mac-address = <&boardconfig 0x16>;
+		mtd-mac-address-increment = <2>;
 		lantiq,wan;
 
 		ethernet@5 {