cpufreq: loongson2: Remove empty exit() callback

The exit() callback is optional, remove the empty one.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>

drivers/cpufreq/loongson2_cpufreq.c

@@ -85,18 +85,12 @@ static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
 	return 0;
 }
 
-static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
-{
-	return 0;
-}
-
 static struct cpufreq_driver loongson2_cpufreq_driver = {
 	.name = "loongson2",
 	.init = loongson2_cpufreq_cpu_init,
 	.verify = cpufreq_generic_frequency_table_verify,
 	.target_index = loongson2_cpufreq_target,
 	.get = cpufreq_generic_get,
-	.exit = loongson2_cpufreq_exit,
 	.attr = cpufreq_generic_attr,
 };