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/maxbcm_defconfig b/configs/maxbcm_defconfig
index 4c6297b..14e788c 100644
--- a/configs/maxbcm_defconfig
+++ b/configs/maxbcm_defconfig
@@ -40,6 +40,7 @@
 CONFIG_PHY_MARVELL=y
 CONFIG_PHY_GIGE=y
 CONFIG_MVNETA=y
+CONFIG_MII=y
 CONFIG_DEBUG_UART_SHIFT=2
 CONFIG_SYS_NS16550=y
 CONFIG_KIRKWOOD_SPI=y