drm/meson: add missing of_node_put

Add an of_node_put when the result of of_graph_get_remote_port_parent is
not available.

An of_node_put is also needed when meson_probe_remote completes.  This was
present at the recursive call, but not in the call from meson_drv_probe.

The semantic match that finds this problem is as follows
(http://coccinelle.lip6.fr):

// <smpl>
@r exists@
local idexpression e;
expression x;
@@
e = of_graph_get_remote_port_parent(...);
... when != x = e
    when != true e == NULL
    when != of_node_put(e)
    when != of_fwnode_handle(e)
(
return e;
|
*return ...;
)
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1547372691-28324-4-git-send-email-Julia.Lawall@lip6.fr

drivers/gpu/drm/meson/meson_drv.c

@@ -388,8 +388,10 @@ static int meson_probe_remote(struct platform_device *pdev,
 		remote_node = of_graph_get_remote_port_parent(ep);
 		if (!remote_node ||
 		    remote_node == parent || /* Ignore parent endpoint */
-		    !of_device_is_available(remote_node))
+		    !of_device_is_available(remote_node)) {
+			of_node_put(remote_node);
 			continue;
+		}
 
 		count += meson_probe_remote(pdev, match, remote, remote_node);
 
@@ -408,10 +410,13 @@ static int meson_drv_probe(struct platform_device *pdev)
 
 	for_each_endpoint_of_node(np, ep) {
 		remote = of_graph_get_remote_port_parent(ep);
-		if (!remote || !of_device_is_available(remote))
+		if (!remote || !of_device_is_available(remote)) {
+			of_node_put(remote);
 			continue;
+		}
 
 		count += meson_probe_remote(pdev, &match, np, remote);
+		of_node_put(remote);
 	}
 
 	if (count && !match)