dm: Move the tree/uclass dump code into its own file

In SPL it is sometimes useful to be able to obtain a dump of the current
driver model state. Since commands are not available, provide a way to
directly call the functions to output this information.

Adjust the existing commands to use these functions.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/dm/util.h

@@ -33,4 +33,10 @@ struct list_head;
  */
 int list_count_items(struct list_head *head);
 
+/* Dump out a tree of all devices */
+void dm_dump_all(void);
+
+/* Dump out a list of uclasses and their devices */
+void dm_dump_uclass(void);
+
 #endif