ARM: dts: imx7d-smegw01: Pass Ethernet aliases

Pass Ethernet aliases, so that the bootloader can properly pass MAC address
to Linux.

This fixes the problem of getting a random MAC address for eth1 in Linux.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>