sunxi: Enable EMAC on the Cubietruck Plus

The Cubietruck Plus has an RTL8211E PHY connected to the EMAC using
RGMII. The PHY is powered by DLDO4 @ 3.3V, while the I/O pins are
powered by DLDO3 @ 2.5V.

This patch enables the EMAC and Realtek PHY drivers in the defconfig.
The device tree file already has the EMAC enabled.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Reviewed-by: NJagan Teki <jagan@amarulasolutions.com>

configs/Cubietruck_plus_defconfig

@@ -20,6 +20,8 @@ CONFIG_CONSOLE_MUX=y
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_DEFAULT_DEVICE_TREE="sun8i-a83t-cubietruck-plus"
+CONFIG_PHY_REALTEK=y
+CONFIG_SUN8I_EMAC=y
 CONFIG_AXP_DLDO3_VOLT=2500
 CONFIG_AXP_DLDO4_VOLT=3300
 CONFIG_AXP_FLDO1_VOLT=1200