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/k2g_evm_defconfig b/configs/k2g_evm_defconfig
index 745ee1e..0c025d8 100644
--- a/configs/k2g_evm_defconfig
+++ b/configs/k2g_evm_defconfig
@@ -48,6 +48,7 @@
 CONFIG_PHY_MARVELL=y
 CONFIG_PHY_MICREL=y
 CONFIG_DM_ETH=y
+CONFIG_MII=y
 CONFIG_REMOTEPROC_TI_POWER=y
 CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y