ARM: dts: meson-sm1-odroid-c4: add ethernet PHY reset

The PHY needs a reset in order to be functionnal for U-Boot, add the old
PHY reset bindings for dwmac until we support the new bindings in the PHY node.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Anand Moon <linux.amoon@gmail.com>