[Telemetry] Output average GPU frequency from power metric

tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py

Index: tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py
diff --git a/tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py b/tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py
index 68c7b92ea73a75a87dc190453485c42ac3f6372e..3151e2eba37bad801e5fa830abb5b393ca62d459 100644
--- a/tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/powermetrics_power_monitor.py
@@ -121,7 +121,15 @@ class PowerMetricsPowerMonitor(power_monitor.PowerMonitor):
 
       assert type(out_data) in [int, float], (
           "Was expecting a number: %s (%s)" % (type(out_data), out_data))
-      return float(out_data)
+
+      out_data = float(out_data)
+
+      # powermetrics reports frequency in hz, convert to mhz if specified in
+      # output.
+      if 'mhz' in metric.out_path[-1]:
+        out_data = out_data / 10 ** 6
+
+      return out_data
 
     power_samples = []
     sample_durations = []