configs: mediatek: enable mt7622 ethernet support

This patch enable mt7622 ethernet support in its defconfig

Signed-off-by: MarkLee <Mark-MC.Lee@mediatek.com>
diff --git a/configs/mt7622_rfb_defconfig b/configs/mt7622_rfb_defconfig
index fa9be04..d8c7ca3 100644
--- a/configs/mt7622_rfb_defconfig
+++ b/configs/mt7622_rfb_defconfig
@@ -33,6 +33,10 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_ETH=y
+CONFIG_PHY_FIXED=y
+CONFIG_MEDIATEK_ETH=y
+CONFIG_NET_RANDOM_ETHADDR=y
+CONFIG_CMD_PING=y
 CONFIG_PINCTRL=y
 CONFIG_PINCONF=y
 CONFIG_PINCTRL_MT7622=y