arm: socfpga: Enable ethernet on ArriaV SoCDK

Synchronise the config options with Cyclone V SoCDK and other boards.
This enables ethernet on the ArriaV SoCDK.

Signed-off-by: Marek Vasut <marex@denx.de>

configs/socfpga_arria5_defconfig

@@ -9,6 +9,9 @@ CONFIG_SPL=y
 CONFIG_OF_CONTROL=y
 CONFIG_SPL_OF_CONTROL=y
 CONFIG_SPI_FLASH=y
+CONFIG_DM_ETH=y
+CONFIG_NETDEVICES=y
+CONFIG_ETH_DESIGNWARE=y
 CONFIG_DM_GPIO=y
 CONFIG_DWAPB_GPIO=y
 CONFIG_SPL_DM=y