Fix log spam when time_in_state file is not available under cpu2/cpu3

tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py

Index: tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
diff --git a/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py b/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
index 8c39a59d3d49453d0b0a9e313bcc201483f2b9e6..2a9bd6048acfeb96412a6d99312e3af2dea5d1ad 100644
--- a/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
+++ b/tools/telemetry/telemetry/internal/platform/power_monitor/sysfs_power_monitor.py
@@ -118,6 +118,11 @@ class SysfsPowerMonitor(power_monitor.PowerMonitor):
     for cpu in self._cpus:
       cpu_freq_path = os.path.join(
           CPU_PATH, cpu, 'cpufreq/stats/time_in_state')
+      if not self._platform.PathExists(cpu_freq_path):
+        logging.warning(
+            'Cannot read cpu frequency times for %s due to %s not existing'
+            % (cpu, cpu_freq_path))
+        continue
       try:
         stats[cpu] = self._platform.GetFileContents(cpu_freq_path)
       except Exception as e: