dm: core: Access device flags through functions

At present flags are stored as part of the device. In preparation for
storing them separately, change the access to go through inline functions.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/devres.c b/drivers/core/devres.c
index 522b07d..313ddc7 100644
--- a/drivers/core/devres.c
+++ b/drivers/core/devres.c
@@ -107,9 +107,9 @@
 
 	devres_log(dev, dr, "ADD");
 	assert_noisy(list_empty(&dr->entry));
-	if (dev->flags & DM_FLAG_PLATDATA_VALID)
+	if (dev_get_flags(dev) & DM_FLAG_PLATDATA_VALID)
 		dr->phase = DEVRES_PHASE_PROBE;
-	else if (dev->flags & DM_FLAG_BOUND)
+	else if (dev_get_flags(dev) & DM_FLAG_BOUND)
 		dr->phase = DEVRES_PHASE_OFDATA;
 	else
 		dr->phase = DEVRES_PHASE_BIND;