dm: Make sure that the root device is probed

The root device should be probed just like any other device. The effect of
this is to mark the device as activated, so that it can be removed (along
with its children) if required.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Vasut <marex@denx.de>
diff --git a/test/dm/core.c b/test/dm/core.c
index be3646b..8c18780 100644
--- a/test/dm/core.c
+++ b/test/dm/core.c
@@ -106,7 +106,7 @@
 	ut_asserteq(0, dm_testdrv_op_count[DM_TEST_OP_POST_PROBE]);
 
 	/* The root device should not be activated until needed */
-	ut_assert(!(dms->root->flags & DM_FLAG_ACTIVATED));
+	ut_assert(dms->root->flags & DM_FLAG_ACTIVATED);
 
 	/*
 	 * We should be able to find the three test devices, and they should