arm64: versal: Enable LIBFDT_OVERLAY

Enable device tree overlay to build all dtbs for Versal with -@ flag to
enable applying overlays.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/xilinx_versal_virt_defconfig b/configs/xilinx_versal_virt_defconfig
index f5ce8a0..2c6c174 100644
--- a/configs/xilinx_versal_virt_defconfig
+++ b/configs/xilinx_versal_virt_defconfig
@@ -70,4 +70,5 @@
 CONFIG_SPI=y
 CONFIG_DM_SPI=y
 CONFIG_FAT_WRITE=y
+CONFIG_OF_LIBFDT_OVERLAY=y
 CONFIG_EFI_LOADER_BOUNCE_BUFFER=y