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/pic32mzdask_defconfig b/configs/pic32mzdask_defconfig
index 9cc7387..8a1a757 100644
--- a/configs/pic32mzdask_defconfig
+++ b/configs/pic32mzdask_defconfig
@@ -32,6 +32,7 @@
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_PIC32=y
 CONFIG_DM_ETH=y
+CONFIG_MII=y
 CONFIG_PIC32_ETH=y
 CONFIG_PINCTRL=y
 # CONFIG_PINCTRL_FULL is not set