Enable Columbia overlay

Bug: 144466013
Change-Id: I9bd96deaf0e5104cedc936d2f6de7a0f955f1740
Tested: Overlay example at https://coral.googlesource.com/docs/+/refs/heads/master/DeviceTreeOverlays.md
diff --git a/configs/imx8mm_columbia_defconfig b/configs/imx8mm_columbia_defconfig
index 4f89254..616da0f 100644
--- a/configs/imx8mm_columbia_defconfig
+++ b/configs/imx8mm_columbia_defconfig
@@ -85,3 +85,5 @@
 
 CONFIG_VIDEO=y
 CONFIG_IMX_SEC_MIPI_DSI=y
+
+CONFIG_OF_LIBFDT_OVERLAY=y