soc/tegra: Don't leak device tree node reference

of_find_node_by_path() acquires a reference to the node returned by it
and that reference needs to be dropped by its caller. soc_is_tegra()
doesn't do that, so fix it.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
[treding: slightly rewrite to avoid inline comparison]
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/soc/tegra/common.c

@@ -22,11 +22,15 @@ static const struct of_device_id tegra_machine_match[] = {
 
 bool soc_is_tegra(void)
 {
+	const struct of_device_id *match;
 	struct device_node *root;
 
 	root = of_find_node_by_path("/");
 	if (!root)
 		return false;
 
-	return of_match_node(tegra_machine_match, root) != NULL;
+	match = of_match_node(tegra_machine_match, root);
+	of_node_put(root);
+
+	return match != NULL;
 }