Move PHY_MICREL and PHY_MICREL_KSZ90X1 to Kconfig

Signed-off-by: Alexandru Gagniuc <alex.g@adaptrum.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/configs/x600_defconfig b/configs/x600_defconfig
index d462891..98b1880 100644
--- a/configs/x600_defconfig
+++ b/configs/x600_defconfig
@@ -36,6 +36,8 @@
 CONFIG_SYS_I2C_DW=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
+CONFIG_PHY_MICREL=y
+CONFIG_PHY_MICREL_KSZ90X1=y
 CONFIG_NETDEVICES=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_USB=y