arm64: renesas: salvator-x: Setup ethernet0 alias for U-Boot

Add an ethernet0 alias for the wired network card so that U-Boot can
find the device-node and add an appropriate "local-mac-address"
property.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795-salvator-x.dts

@@ -18,6 +18,7 @@ / {
 	aliases {
 		serial0 = &scif2;
 		serial1 = &scif1;
+		ethernet0 = &avb;
 	};
 
 	chosen {