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/nand/raw/nand_util.c b/drivers/mtd/nand/raw/nand_util.c
index fc2235c..f3c8f7f 100644
--- a/drivers/mtd/nand/raw/nand_util.c
+++ b/drivers/mtd/nand/raw/nand_util.c
@@ -24,6 +24,7 @@
 #include <malloc.h>
 #include <memalign.h>
 #include <div64.h>
+#include <dm/devres.h>
 
 #include <linux/errno.h>
 #include <linux/mtd/mtd.h>