gpu: drm: sti_vdo: add missing of_node_put after calling of_parse_phandle

of_node_put needs to be called when the device node which is got
from of_parse_phandle has finished using.

Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Vincent Abriou <vincent.abriou@st.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1467684294-20111-4-git-send-email-peter.chen@nxp.com

drivers/gpu/drm/sti/sti_dvo.c

@@ -580,6 +580,7 @@ static int sti_dvo_probe(struct platform_device *pdev)
 	dvo->panel_node = of_parse_phandle(np, "sti,panel", 0);
 	if (!dvo->panel_node)
 		DRM_ERROR("No panel associated to the dvo output\n");
+	of_node_put(dvo->panel_node);
 
 	platform_set_drvdata(pdev, dvo);