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/lib/crypto/pkcs7_parser.c b/lib/crypto/pkcs7_parser.c
index bf9e7e8..f5dda11 100644
--- a/lib/crypto/pkcs7_parser.c
+++ b/lib/crypto/pkcs7_parser.c
@@ -7,6 +7,7 @@
 
 #define pr_fmt(fmt) "PKCS7: "fmt
 #ifdef __UBOOT__
+#include <dm/devres.h>
 #include <linux/bitops.h>
 #include <linux/compat.h>
 #endif