vgv7519: support more recent board release with vrx288 v1.2

The existance of this new board has been confirmed and tested by the guy on this commit

https://github.com/openwrt-vgv7519/uboot-bin/commit/76fdd8e638f81e324ffe77856481bd147398f6e8

SVN-Revision: 43072

target/linux/lantiq/dts/VGV7519.dtsi

@@ -219,7 +219,8 @@
 
 	gphy-xrx200 {
 		compatible = "lantiq,phy-xrx200";
-		firmware = "lantiq/vr9_phy11g_a1x.bin";
+		firmware1 = "lantiq/vr9_phy11g_a1x.bin";	/*VR9 1.1*/
+		firmware2 = "lantiq/vr9_phy11g_a2x.bin";	/*VR9 1.2*/
 		phys = [ 00 01 ];
 	};