cpufreq: qcom-hw: enable boost support

At least on sdm850, the 2956800 khz is detected as a boost frequency in
function qcom_cpufreq_hw_read_lut().  Let's enable boost support by
calling cpufreq_enable_boost_support(), so that we can get the boost
frequency by switching it on via 'boost' sysfs entry like below.

 $ echo 1 > /sys/devices/system/cpu/cpufreq/boost
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/qcom-cpufreq-hw.c

@@ -347,6 +347,12 @@ static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
 
 	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
 
+	if (policy_has_boost_freq(policy)) {
+		ret = cpufreq_enable_boost_support();
+		if (ret)
+			dev_warn(cpu_dev, "failed to enable boost: %d\n", ret);
+	}
+
 	return 0;
 error:
 	devm_iounmap(dev, base);