cpufreq: Make cpufreq_boost_supported() static

cpufreq_boost_supported() is not used outside of cpufreq.c, so make
it static.

While at it, refactor it as a one-liner (which it really is).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/cpufreq.c

@@ -2330,14 +2330,10 @@ int cpufreq_boost_trigger_state(int state)
 	return ret;
 }
 
-int cpufreq_boost_supported(void)
+static bool cpufreq_boost_supported(void)
 {
-	if (likely(cpufreq_driver))
-		return cpufreq_driver->boost_supported;
-
-	return 0;
+	return likely(cpufreq_driver) && cpufreq_driver->boost_supported;
 }
-EXPORT_SYMBOL_GPL(cpufreq_boost_supported);
 
 static int create_boost_sysfs_file(void)
 {

include/linux/cpufreq.h

@@ -574,7 +574,6 @@ ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
 
 #ifdef CONFIG_CPU_FREQ
 int cpufreq_boost_trigger_state(int state);
-int cpufreq_boost_supported(void);
 int cpufreq_boost_enabled(void);
 int cpufreq_enable_boost_support(void);
 bool policy_has_boost_freq(struct cpufreq_policy *policy);
@@ -583,10 +582,6 @@ static inline int cpufreq_boost_trigger_state(int state)
 {
 	return 0;
 }
-static inline int cpufreq_boost_supported(void)
-{
-	return 0;
-}
 static inline int cpufreq_boost_enabled(void)
 {
 	return 0;