cpufreq: Return -EOPNOTSUPP if no policy supports boost

In cpufreq_boost_trigger_state(), if none of the the policies support
boost, policy_set_boost() will not be called and this function will
return 0.

But it is better to return an error to indicate that the platform
doesn't support boost.

Signed-off-by: Lifeng Zheng <zhenglifeng1@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jie Zhan <zhanjie9@hisilicon.com>
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20251202072727.1368285-2-zhenglifeng1@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Lifeng Zheng

drivers/cpufreq/cpufreq.c

@@ -2803,7 +2803,7 @@ static int cpufreq_boost_trigger_state(int state)
 {
 	struct cpufreq_policy *policy;
 	unsigned long flags;
-	int ret = 0;
+	int ret = -EOPNOTSUPP;
 
 	/*
 	 * Don't compare 'cpufreq_driver->boost_enabled' with 'state' here to
@@ -2823,6 +2823,10 @@ static int cpufreq_boost_trigger_state(int state)
 		if (ret)
 			goto err_reset_state;
 	}
+
+	if (ret)
+		goto err_reset_state;
+
 	cpus_read_unlock();
 
 	return 0;