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/include/test/ut.h b/include/test/ut.h
index 99bbb12..6ab2f88 100644
--- a/include/test/ut.h
+++ b/include/test/ut.h
@@ -11,6 +11,7 @@
 #include <command.h>
 #include <hexdump.h>
 #include <linux/err.h>
+#include <test/test.h>
 
 struct unit_test_state;