drm/fsl-dcu: check for clk_prepare_enable() error

clk_prepare_enable() may fail, so we should better check its return
value.

Also place the of_node_put() function right after clk_prepare_enable(),
in order to avoid calling of_node_put() twice in case clk_prepare_enable()
fails.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>

drivers/gpu/drm/fsl-dcu/fsl_tcon.c

@@ -87,9 +87,13 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
 		goto err_node_put;
 	}
 
-	of_node_put(np);
-	clk_prepare_enable(tcon->ipg_clk);
+	ret = clk_prepare_enable(tcon->ipg_clk);
+	if (ret) {
+		dev_err(dev, "Couldn't enable the TCON clock\n");
+		goto err_node_put;
+	}
 
+	of_node_put(np);
 	dev_info(dev, "Using TCON in bypass mode\n");
 
 	return tcon;