dm: core: Drop header files from dm/test.h

These header file should not be included in other header files. Remove
them and add to each individual file. Add test/test.h to test/ui.h since
that is a reasonable place.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/virtio.c b/test/dm/virtio.c
index 4a0c0b2..6361cd5 100644
--- a/test/dm/virtio.c
+++ b/test/dm/virtio.c
@@ -9,9 +9,10 @@
 #include <virtio.h>
 #include <virtio_ring.h>
 #include <dm/device-internal.h>
-#include <dm/uclass-internal.h>
 #include <dm/root.h>
 #include <dm/test.h>
+#include <dm/uclass-internal.h>
+#include <test/test.h>
 #include <test/ut.h>
 
 /* Basic test of the virtio uclass */