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/Cyrus_P5020_defconfig b/configs/Cyrus_P5020_defconfig
index d2e7e73..cf61c62 100644
--- a/configs/Cyrus_P5020_defconfig
+++ b/configs/Cyrus_P5020_defconfig
@@ -30,8 +30,8 @@
 CONFIG_PHYLIB=y
 CONFIG_PHY_MICREL=y
 CONFIG_PHY_MICREL_KSZ90X1=y
-CONFIG_NETDEVICES=y
 CONFIG_E1000=y
+CONFIG_MII=y
 CONFIG_SYS_NS16550=y
 CONFIG_SPI=y
 CONFIG_FSL_ESPI=y