cpufreq: cpufreq-cpu0: clk_round_rate() can return a zero upon error

Treat both negative and zero return values from clk_round_rate()
as errors.  This is needed since subsequent patches will convert
clk_round_rate()'s return value to be an unsigned type, rather
than a signed type, since some clock sources can generate rates
higher than (2^31)-1 Hz.

Eventually, when calling clk_round_rate(), only a return value of
zero will be considered a error.  All other values will be
considered valid rates.  The comparison against values less than
0 is kept to preserve the correct behavior in the meantime.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/cpufreq-cpu0.c

@@ -44,7 +44,7 @@ static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index)
 	int ret;
 
 	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
-	if (freq_Hz < 0)
+	if (freq_Hz <= 0)
 		freq_Hz = freq_table[index].frequency * 1000;
 
 	freq_exact = freq_Hz;