Convert CONFIG_MII et al to Kconfig

This converts the following to Kconfig:
   CONFIG_MII
   CONFIG_DRIVER_TI_EMAC

Signed-off-by: Adam Ford <aford173@gmail.com>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/mx6ul_14x14_evk_defconfig b/configs/mx6ul_14x14_evk_defconfig
index 86f3c1f..038f3a6 100644
--- a/configs/mx6ul_14x14_evk_defconfig
+++ b/configs/mx6ul_14x14_evk_defconfig
@@ -43,6 +43,7 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_PHYLIB=y
 CONFIG_PHY_MICREL=y
+CONFIG_MII=y
 CONFIG_SPI=y
 CONFIG_FSL_QSPI=y
 CONFIG_USB=y