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/gpio/dwapb_gpio.c b/drivers/gpio/dwapb_gpio.c
index 2eb1547..58e3e7b 100644
--- a/drivers/gpio/dwapb_gpio.c
+++ b/drivers/gpio/dwapb_gpio.c
@@ -12,6 +12,7 @@
 #include <asm/io.h>
 #include <dm.h>
 #include <dm/device-internal.h>
+#include <dm/devres.h>
 #include <dm/lists.h>
 #include <dm/root.h>
 #include <errno.h>