Convert CONFIG_PHYLIB et al to Kconfig

This converts the following to Kconfig:
   CONFIG_PHYLIB
   CONFIG_BITBANGMII
   CONFIG_MV88E6352_SWITCH
   CONFIG_MV88E61XX_SWITCH
   CONFIG_PHYLIB_10G
   CONFIG_PHY_AQUANTIA
   CONFIG_PHY_ATHEROS
   CONFIG_PHY_BROADCOM
   CONFIG_PHY_CORTINA
   CONFIG_PHY_DAVICOM
   CONFIG_PHY_ET1011C
   CONFIG_PHY_LXT
   CONFIG_PHY_MARVELL
   CONFIG_PHY_MICREL
   CONFIG_PHY_NATSEMI
   CONFIG_PHY_REALTEK
   CONFIG_RTL8211X_PHY_FORCE_MASTER
   CONFIG_PHY_SMSC
   CONFIG_PHY_TERANETICS
   CONFIG_PHY_TI
   CONFIG_PHY_VITESSE
   CONFIG_PHY_XILINX

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/silk_defconfig b/configs/silk_defconfig
index 89ef1d4..5daa084 100644
--- a/configs/silk_defconfig
+++ b/configs/silk_defconfig
@@ -73,6 +73,7 @@
 CONFIG_DM_SPI_FLASH=y
 CONFIG_SPI_FLASH_SPANSION=y
 CONFIG_SPI_FLASH_MTD=y
+CONFIG_BITBANGMII=y
 CONFIG_PHY_MICREL=y
 CONFIG_PHY_MICREL_KSZ8XXX=y
 CONFIG_DM_ETH=y