drm/lima: Fix opp clkname setting in case of missing regulator

Commit d8c32d39 ("drm/lima: Migrate to dev_pm_opp_set_config()")
introduced a regression as it may undo the clk_names setting in case
the optional regulator is missing. This resulted in test and performance
regressions with lima.

Restore the old behavior where clk_names is set separately so it is not
undone in case of a missing optional regulator.

Fixes: d8c32d39 ("drm/lima: Migrate to dev_pm_opp_set_config()")
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221027073200.3885839-1-nunes.erico@gmail.com

drivers/gpu/drm/lima/lima_devfreq.c

@@ -112,11 +112,6 @@ int lima_devfreq_init(struct lima_device *ldev)
 	unsigned long cur_freq;
 	int ret;
 	const char *regulator_names[] = { "mali", NULL };
-	const char *clk_names[] = { "core", NULL };
-	struct dev_pm_opp_config config = {
-		.regulator_names = regulator_names,
-		.clk_names = clk_names,
-	};
 
 	if (!device_property_present(dev, "operating-points-v2"))
 		/* Optional, continue without devfreq */
@@ -124,7 +119,15 @@ int lima_devfreq_init(struct lima_device *ldev)
 
 	spin_lock_init(&ldevfreq->lock);
 
-	ret = devm_pm_opp_set_config(dev, &config);
+	/*
+	 * clkname is set separately so it is not affected by the optional
+	 * regulator setting which may return error.
+	 */
+	ret = devm_pm_opp_set_clkname(dev, "core");
+	if (ret)
+		return ret;
+
+	ret = devm_pm_opp_set_regulators(dev, regulator_names);
 	if (ret) {
 		/* Continue if the optional regulator is missing */
 		if (ret != -ENODEV)