colibri_imx7: migrate to DM_ETH

Migrate to DM_ETH and remove hardcoded pinmux configuration.

Signed-off-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
diff --git a/configs/colibri_imx7_emmc_defconfig b/configs/colibri_imx7_emmc_defconfig
index ac2fa0e..9b42a5b 100644
--- a/configs/colibri_imx7_emmc_defconfig
+++ b/configs/colibri_imx7_emmc_defconfig
@@ -62,6 +62,9 @@
 CONFIG_PHYLIB=y
 CONFIG_PHY_MICREL=y
 CONFIG_PHY_MICREL_KSZ8XXX=y
+CONFIG_DM_ETH=y
+CONFIG_DM_MDIO=y
+CONFIG_FEC_MXC=y
 CONFIG_MII=y
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_IMX7=y