OPP: Improve _find_table_of_opp_np()

Make _find_table_of_opp_np() more efficient by using of_get_parent() to
find the parent OPP table node.
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/opp/of.c

@@ -114,19 +114,25 @@ static struct device_node *of_parse_required_opp(struct device_node *np,
 static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
 {
 	struct opp_table *opp_table;
-	struct dev_pm_opp *opp;
+	struct device_node *opp_table_np;
 
 	lockdep_assert_held(&opp_table_lock);
 
+	opp_table_np = of_get_parent(opp_np);
+	if (!opp_table_np)
+		goto err;
+
+	/* It is safe to put the node now as all we need now is its address */
+	of_node_put(opp_table_np);
+
 	list_for_each_entry(opp_table, &opp_tables, node) {
-		opp = _find_opp_of_np(opp_table, opp_np);
-		if (opp) {
-			dev_pm_opp_put(opp);
+		if (opp_table_np == opp_table->np) {
 			_get_opp_table_kref(opp_table);
 			return opp_table;
 		}
 	}
 
+err:
 	return ERR_PTR(-ENODEV);
 }