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/net/mvpp2.c b/drivers/net/mvpp2.c
index b234b41..105fdc9 100644
--- a/drivers/net/mvpp2.c
+++ b/drivers/net/mvpp2.c
@@ -17,12 +17,14 @@
 #include <cpu_func.h>
 #include <dm.h>
 #include <dm/device-internal.h>
+#include <dm/devres.h>
 #include <dm/lists.h>
 #include <net.h>
 #include <netdev.h>
 #include <config.h>
 #include <malloc.h>
 #include <asm/io.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <phy.h>
 #include <miiphy.h>