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/clk/meson/g12a.c b/drivers/clk/meson/g12a.c
index 1b2523b..686d94e 100644
--- a/drivers/clk/meson/g12a.c
+++ b/drivers/clk/meson/g12a.c
@@ -14,6 +14,7 @@
 #include <syscon.h>
 #include <div64.h>
 #include <dt-bindings/clock/g12a-clkc.h>
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include "clk_meson.h"