dm: core: Require users of devres to include the header

At present devres.h is included in all files that include dm.h but few
make use of it. Also this pulls in linux/compat which adds several more
headers. Drop the automatic inclusion and require files to include devres
themselves. This provides a good indication of which files use devres.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
diff --git a/fs/yaffs2/yaffs_allocator.c b/fs/yaffs2/yaffs_allocator.c
index 611061f..961dc22 100644
--- a/fs/yaffs2/yaffs_allocator.c
+++ b/fs/yaffs2/yaffs_allocator.c
@@ -15,6 +15,7 @@
 #include "yaffs_guts.h"
 #include "yaffs_trace.h"
 #include "yportenv.h"
+#include <dm/devres.h>
 
 /*
  * Each entry in yaffs_tnode_list and yaffs_obj_list hold blocks