drm/tegra: Fix reference leak in tegra_dsi_ganged_probe

The reference taken by 'of_find_device_by_node()' must be released when
not needed anymore. Add put_device() call to fix this.

Fixes: e94236c ("drm/tegra: dsi: Add ganged mode support")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dsi.c

@@ -1538,8 +1538,10 @@ static int tegra_dsi_ganged_probe(struct tegra_dsi *dsi)
 		dsi->slave = platform_get_drvdata(gangster);
 		of_node_put(np);
 
-		if (!dsi->slave)
+		if (!dsi->slave) {
+			put_device(&gangster->dev);
 			return -EPROBE_DEFER;
+		}
 
 		dsi->slave->master = dsi;
 	}