arch_topology: validate input frequencies to arch_set_freq_scale()

The current frequency passed to arch_set_freq_scale() could end up
being 0, signaling an error in setting a new frequency. Also, if the
maximum frequency in 0, this will result in a division by 0 error.

Therefore, validate these input values before using them for the
setting of the frequency scale factor.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/arch_topology.c

@@ -33,6 +33,9 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
 	unsigned long scale;
 	int i;
 
+	if (WARN_ON_ONCE(!cur_freq || !max_freq))
+		return;
+
 	/*
 	 * If the use of counters for FIE is enabled, just return as we don't
 	 * want to update the scale factor with information from CPUFREQ.