of: Decrement refcount of previous endpoint in of_graph_get_next_endpoint

Decrementing the reference count of the previous endpoint node allows to
use the of_graph_get_next_endpoint function in a for_each_... style macro.
All current users of this function that pass a non-NULL prev parameter
(that is, soc_camera and imx-drm) are changed to not decrement the passed
prev argument's refcount themselves.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 0a8aeb8..05b20f1 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2086,8 +2086,7 @@
  * @prev: previous endpoint node, or NULL to get first
  *
  * Return: An 'endpoint' node pointer with refcount incremented. Refcount
- * of the passed @prev node is not decremented, the caller have to use
- * of_node_put() on it when done.
+ * of the passed @prev node is decremented.
  */
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *prev)
@@ -2123,12 +2122,6 @@
 		if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
 			      __func__, prev->full_name))
 			return NULL;
-
-		/*
-		 * Avoid dropping prev node refcount to 0 when getting the next
-		 * child below.
-		 */
-		of_node_get(prev);
 	}
 
 	while (1) {