arm64: dts: imx8mq: Add ethernet alias

Add ethernet alias, so bootloader code can use this to find the
primary ethernet device, and set the MAC address.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq.dtsi

@@ -20,6 +20,7 @@
 	#size-cells = <2>;
 
 	aliases {
+		ethernet0 = &fec1;
 		gpio0 = &gpio1;
 		gpio1 = &gpio2;
 		gpio2 = &gpio3;