[CPUFREQ] conservative: fix dbs_cpufreq_notifier so freq is not locked

When someone added the dbs_cpufreq_notifier section to the governor the
code ended up causing the frequency to only fall.  This is because
requested_freq is tinkered with and that should only modified if it has
an invlaid value due to changes in the available frequency ranges

This should fix #10055.
Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
Signed-off-by: Dave Jones <davej@redhat.com>

drivers/cpufreq/cpufreq_conservative.c

@@ -137,9 +137,20 @@ dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 	struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info,
 							freq->cpu);
 
+	struct cpufreq_policy *policy;
+
 	if (!this_dbs_info->enable)
 		return 0;
 
+	policy = this_dbs_info->cur_policy;
+
+	/*
+	 * we only care if our internally tracked freq moves outside
+	 * the 'valid' ranges of freqency available to us otherwise
+	 * we do not change it
+	*/
+	if (this_dbs_info->requested_freq > policy->max
+			|| this_dbs_info->requested_freq < policy->min)
 		this_dbs_info->requested_freq = freq->new;
 
 	return 0;