ARM: dts: sun8i: v40: bananapi-m2-berry: Enable GMAC ethernet controller

Just like the Bananapi M2 Ultra, the Bananapi M2 Berry has a Realtek
RTL8211E RGMII PHY tied to the GMAC.
The PMIC's DC1SW output provides power for the PHY, while the ALDO2
output provides I/O voltages on both sides.

Signed-off-by: Pablo Greco <pgreco@centosproject.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>