arm64: dts: stratix10: add ethernet aliases

Add ethernet<n> alias for all gmacs on the devkit.

Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
v2: move ethernet aliases to board file

arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dts

@@ -21,6 +21,9 @@
 
 	aliases {
 		serial0 = &uart0;
+		ethernet0 = &gmac0;
+		ethernet1 = &gmac1;
+		ethernet2 = &gmac2;
 	};
 
 	chosen {