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/calimain_defconfig b/configs/calimain_defconfig
index 41d531b..ae517e0 100644
--- a/configs/calimain_defconfig
+++ b/configs/calimain_defconfig
@@ -27,4 +27,6 @@
 CONFIG_DA8XX_GPIO=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_MII=y
+CONFIG_DRIVER_TI_EMAC=y
 CONFIG_SYS_NS16550=y