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/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 89ca90f..4038b7f 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -86,6 +86,7 @@
  */
 
 #ifndef __UBOOT__
+#include <dm/devres.h>
 #include <linux/slab.h>
 #include <linux/crc32.h>
 #include <linux/freezer.h>