test: Move dm_extended_scan() to test_pre_run()

Move this step over to the pre-run function.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/test-dm.c b/test/dm/test-dm.c
index 69a0349..4cb0da1 100644
--- a/test/dm/test-dm.c
+++ b/test/dm/test-dm.c
@@ -93,9 +93,6 @@
 		ut_assertok(dm_scan_plat(false));
 	if (test->flags & UT_TESTF_PROBE_TEST)
 		ut_assertok(do_autoprobe(uts));
-	if (!CONFIG_IS_ENABLED(OF_PLATDATA) &&
-	    (test->flags & UT_TESTF_SCAN_FDT))
-		ut_assertok(dm_extended_scan(false));
 
 	ut_assertok(test_pre_run(uts, test));
 
diff --git a/test/test-main.c b/test/test-main.c
index 9c60009..a971fe0 100644
--- a/test/test-main.c
+++ b/test/test-main.c
@@ -6,7 +6,10 @@
 
 #include <common.h>
 #include <console.h>
+#include <dm.h>
+#include <dm/root.h>
 #include <test/test.h>
+#include <test/ut.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -16,6 +19,10 @@
 	if (!(test->flags & UT_TESTF_DM))
 		uts->start = mallinfo();
 
+	if (!CONFIG_IS_ENABLED(OF_PLATDATA) &&
+	    (test->flags & UT_TESTF_SCAN_FDT))
+		ut_assertok(dm_extended_scan(false));
+
 	if (test->flags & UT_TESTF_CONSOLE_REC) {
 		int ret = console_record_reset_enable();