cpufreq: Replace magic number

Setting the length of str_governor with a magic number could cause
overflow when max length increases, it is better to use the defined
macro in this case.

Signed-off-by: Bowen Yu <yubowen8@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://patch.msgid.link/20250519070908.930879-1-yubowen8@huawei.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: Bowen Yu

drivers/cpufreq/cpufreq.c

@@ -806,7 +806,7 @@ static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
 static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
 					const char *buf, size_t count)
 {
-	char str_governor[16];
+	char str_governor[CPUFREQ_NAME_LEN];
 	int ret;
 
 	ret = sscanf(buf, "%15s", str_governor);