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/ubifs/debug.c b/fs/ubifs/debug.c
index 782aa9a..6835f86 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -16,6 +16,7 @@
  */
 
 #include <hexdump.h>
+#include <dm/devres.h>
 
 #ifndef __UBOOT__
 #include <linux/module.h>