rockchip: configs: Enable networking support on rk3288 boards

At current, only firefly and rock2 have network enabled.
Let's enable other boards.

Signed-off-by: Jacob Chen <jacob2.chen@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/popmetal-rk3288_defconfig b/configs/popmetal-rk3288_defconfig
index 7b5ed94..dfc84b9 100644
--- a/configs/popmetal-rk3288_defconfig
+++ b/configs/popmetal-rk3288_defconfig
@@ -41,6 +41,10 @@
 CONFIG_SYS_I2C_ROCKCHIP=y
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_DM_ETH=y
+CONFIG_NETDEVICES=y
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_GMAC_ROCKCHIP=y
 CONFIG_PINCTRL=y
 CONFIG_SPL_PINCTRL=y
 # CONFIG_SPL_PINCTRL_FULL is not set