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/A10s-OLinuXino-M_defconfig b/configs/A10s-OLinuXino-M_defconfig
index 09c6270..ab576ba 100644
--- a/configs/A10s-OLinuXino-M_defconfig
+++ b/configs/A10s-OLinuXino-M_defconfig
@@ -14,6 +14,7 @@
 # CONFIG_CMD_FLASH is not set
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
+CONFIG_MII=y
 CONFIG_SUN4I_EMAC=y
 CONFIG_AXP152_POWER=y
 CONFIG_CONS_INDEX=2