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/pico-imx6ul_defconfig b/configs/pico-imx6ul_defconfig
index 9d16dd6..19f8fc4 100644
--- a/configs/pico-imx6ul_defconfig
+++ b/configs/pico-imx6ul_defconfig
@@ -28,6 +28,7 @@
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_DFU_MMC=y
 CONFIG_PHYLIB=y
+CONFIG_PHY_MICREL=y
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_GADGET=y