clk: oxnas: Hold reference returned by of_get_parent()

In oxnas_stdclk_probe(), we need to hold the reference returned by
of_get_parent() and use it to call of_node_put() for refcount
balance.

Fixes: 0bbd72b4 ("clk: Add Oxford Semiconductor OXNAS Standard Clocks")
Signed-off-by: Liang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220628143155.170550-1-windhl@126.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk-oxnas.c

@@ -207,7 +207,7 @@ static const struct of_device_id oxnas_stdclk_dt_ids[] = {
 
 static int oxnas_stdclk_probe(struct platform_device *pdev)
 {
-	struct device_node *np = pdev->dev.of_node;
+	struct device_node *np = pdev->dev.of_node, *parent_np;
 	const struct oxnas_stdclk_data *data;
 	struct regmap *regmap;
 	int ret;
@@ -215,7 +215,9 @@ static int oxnas_stdclk_probe(struct platform_device *pdev)
 
 	data = of_device_get_match_data(&pdev->dev);
 
-	regmap = syscon_node_to_regmap(of_get_parent(np));
+	parent_np = of_get_parent(np);
+	regmap = syscon_node_to_regmap(parent_np);
+	of_node_put(parent_np);
 	if (IS_ERR(regmap)) {
 		dev_err(&pdev->dev, "failed to have parent regmap\n");
 		return PTR_ERR(regmap);