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/edb9315a_defconfig b/configs/edb9315a_defconfig
index b34f5c9..72238c5 100644
--- a/configs/edb9315a_defconfig
+++ b/configs/edb9315a_defconfig
@@ -38,6 +38,7 @@
 CONFIG_LED_STATUS_GREEN=0
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_MII=y
 CONFIG_CONS_INDEX=0
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y