Remove undef of CONFIG_CMD_IMPORTENV for Columbia

Change-Id: Ic3509576dbae8b035a903976dc5a8881cf8264aa
diff --git a/include/configs/imx8mm_columbia.h b/include/configs/imx8mm_columbia.h
index 9ac477e..27cc681 100644
--- a/include/configs/imx8mm_columbia.h
+++ b/include/configs/imx8mm_columbia.h
@@ -84,7 +84,6 @@
 #define CONFIG_BOARD_LATE_INIT
 
 #undef CONFIG_CMD_EXPORTENV
-#undef CONFIG_CMD_IMPORTENV
 #undef CONFIG_CMD_IMLS
 
 #undef CONFIG_CMD_CRC32