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/bk4r1_defconfig b/configs/bk4r1_defconfig
index e991a04..63b9514 100644
--- a/configs/bk4r1_defconfig
+++ b/configs/bk4r1_defconfig
@@ -34,6 +34,7 @@
 CONFIG_SPI_FLASH_STMICRO=y
 CONFIG_SPI_FLASH_MTD=y
 CONFIG_PHYLIB=y
+CONFIG_PHY_MICREL=y
 CONFIG_DM_SERIAL=y
 CONFIG_FSL_LPUART=y
 CONFIG_DM_SPI=y