cpufreq: tegra: call CPUFREQ_POSTCHANGE notfier in error cases

PRECHANGE and POSTCHANGE notifiers must be called in groups, i.e either both
should be called or both shouldn't be.

In case we have started PRECHANGE notifier and found an error, we must call
POSTCHANGE notifier with freqs.new = freqs.old to guarantee that sequence of
calling notifiers is complete.

This patch fixes it.
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>

drivers/cpufreq/tegra-cpufreq.c

@@ -138,12 +138,12 @@ static int tegra_update_cpu_speed(struct cpufreq_policy *policy,
 	if (ret) {
 		pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
 			freqs.new);
-		return ret;
+		freqs.new = freqs.old;
 	}
 
 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 
-	return 0;
+	return ret;
 }
 
 static unsigned long tegra_cpu_highest_speed(void)