ARM: dts: exynos: Add an alias for the Ethernet interface on Odroid XU3

Add an alias to enable bootloaders to find the Ethernet
interface and assign a MAC address.

Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Link: https://lore.kernel.org/r/20201103184412.18874-3-l.stelmach@samsung.com


Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>