soc: fsl: guts: reuse machine name from device tree

Reuse the string machine from the device tree data structure instead
of duplicating the data again.  This also prevents a potential memory
allocation failure that was not handled previously.  Also fixes an early
put of root device node.
Reported-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Li Yang <leoyang.li@nxp.com>

drivers/soc/fsl/guts.c

@@ -32,6 +32,7 @@ struct fsl_soc_die_attr {
 static struct guts *guts;
 static struct soc_device_attribute soc_dev_attr;
 static struct soc_device *soc_dev;
+static struct device_node *root;
 
 
 /* SoC die attribute definition for QorIQ platform */
@@ -132,7 +133,7 @@ EXPORT_SYMBOL(fsl_guts_get_svr);
 
 static int fsl_guts_probe(struct platform_device *pdev)
 {
-	struct device_node *root, *np = pdev->dev.of_node;
+	struct device_node *np = pdev->dev.of_node;
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	const struct fsl_soc_die_attr *soc_die;
@@ -155,9 +156,8 @@ static int fsl_guts_probe(struct platform_device *pdev)
 	root = of_find_node_by_path("/");
 	if (of_property_read_string(root, "model", &machine))
 		of_property_read_string_index(root, "compatible", 0, &machine);
-	of_node_put(root);
 	if (machine)
-		soc_dev_attr.machine = devm_kstrdup(dev, machine, GFP_KERNEL);
+		soc_dev_attr.machine = machine;
 
 	svr = fsl_guts_get_svr();
 	soc_die = fsl_soc_die_match(svr, fsl_soc_die);
@@ -192,6 +192,7 @@ static int fsl_guts_probe(struct platform_device *pdev)
 static int fsl_guts_remove(struct platform_device *dev)
 {
 	soc_device_unregister(soc_dev);
+	of_node_put(root);
 	return 0;
 }