[crosperf] Fix telemetry results parsing.

Many telemetry results fields now contain multiple values. This CL
fixes crosperf to accomodate that.

BUG=None
TEST=Ran crosperf with change and it worked.

Change-Id: Iccb8926223c8447b72d51f413756f5dbc09f89de
diff --git a/crosperf/results_cache.py b/crosperf/results_cache.py
index e909656..082bd32 100644
--- a/crosperf/results_cache.py
+++ b/crosperf/results_cache.py
@@ -319,9 +319,10 @@
           if 'value' in value_dict:
             result = value_dict['value']
           elif 'values' in value_dict:
-            result = value_dict['values'][0]
             if len(value_dict['values']) > 1:
-              raise RuntimeError('Too many values returned for %s.' % item)
+              result = value_dict['values']
+            else:
+              result = value_dict['values'][0]
           units = value_dict['units']
           new_value = [result, units]
           keyvals[keyname] = new_value