dm: Allow driver model tests only for sandbox

The GPIO tests require the sandbox GPIO driver, so cannot be run on other
platforms. Similarly for the 'dm test' command.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 4e9afe6..c0f2135 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -15,4 +15,6 @@
 # subsystem you must add sandbox tests here.
 obj-$(CONFIG_DM_TEST) += core.o
 obj-$(CONFIG_DM_TEST) += ut.o
+ifneq ($(CONFIG_SANDBOX),)
 obj-$(CONFIG_DM_GPIO) += gpio.o
+endif
diff --git a/test/dm/cmd_dm.c b/test/dm/cmd_dm.c
index 083f15c..180661b 100644
--- a/test/dm/cmd_dm.c
+++ b/test/dm/cmd_dm.c
@@ -93,16 +93,23 @@
 	return 0;
 }
 
+#ifdef CONFIG_DM_TEST
 static int do_dm_test(cmd_tbl_t *cmdtp, int flag, int argc,
 			  char * const argv[])
 {
 	return dm_test_main();
 }
+#define TEST_HELP "\ndm test         Run tests"
+#else
+#define TEST_HELP
+#endif
 
 static cmd_tbl_t test_commands[] = {
 	U_BOOT_CMD_MKENT(tree, 0, 1, do_dm_dump_all, "", ""),
 	U_BOOT_CMD_MKENT(uclass, 1, 1, do_dm_dump_uclass, "", ""),
+#ifdef CONFIG_DM_TEST
 	U_BOOT_CMD_MKENT(test, 1, 1, do_dm_test, "", ""),
+#endif
 };
 
 static int do_dm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
@@ -128,6 +135,6 @@
 	dm,	2,	1,	do_dm,
 	"Driver model low level access",
 	"tree         Dump driver model tree\n"
-	"dm uclass        Dump list of instances for each uclass\n"
-	"dm test         Run tests"
+	"dm uclass        Dump list of instances for each uclass"
+	TEST_HELP
 );