dm: Add a 'dm' command for testing

This command is not required for driver model operation, but can be useful
for testing. It provides simple dumps of internal data structures.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com>
Signed-off-by: Viktor Křivák <viktor.krivak@gmail.com>
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 6af85b9..4e9afe6 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -4,6 +4,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
+obj-$(CONFIG_CMD_DM) += cmd_dm.o
 obj-$(CONFIG_DM_TEST) += test-driver.o
 obj-$(CONFIG_DM_TEST) += test-fdt.o
 obj-$(CONFIG_DM_TEST) += test-main.o