imx: imx8mm-evk: enable ethernet

add phy-reset-gpios to reset phy
Add board_phy_config to configure phy
Enable DM_ETH

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/configs/imx8mm_evk_defconfig b/configs/imx8mm_evk_defconfig
index 4cbc62f..9bf5c45 100644
--- a/configs/imx8mm_evk_defconfig
+++ b/configs/imx8mm_evk_defconfig
@@ -35,6 +35,9 @@
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y
 CONFIG_CMD_MMC=y
+CONFIG_CMD_DHCP=y
+CONFIG_CMD_MII=y
+CONFIG_CMD_PING=y
 CONFIG_CMD_CACHE=y
 CONFIG_CMD_REGULATOR=y
 CONFIG_CMD_EXT2=y
@@ -62,7 +65,11 @@
 CONFIG_SUPPORT_EMMC_BOOT=y
 CONFIG_FSL_ESDHC_IMX=y
 CONFIG_PHYLIB=y
+CONFIG_PHY_ATHEROS=y
 CONFIG_DM_ETH=y
+CONFIG_PHY_GIGE=y
+CONFIG_FEC_MXC=y
+CONFIG_MII=y
 CONFIG_PINCTRL=y
 CONFIG_SPL_PINCTRL=y
 CONFIG_PINCTRL_IMX8M=y