oe-build-perf-report: use correct x-axis max value in html charts

(From OE-Core rev: 1d99b018c2b6a44b9db2f2ede113e64dae751eee)

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/oe-build-perf-report

@@ -373,7 +373,7 @@ def print_html_report(data, id_comp):
 
     # Chart options
     chart_opts = {'haxis': {'min': get_data_item(data[0][0], 'layers.meta.commit_count'),
-                            'max': get_data_item(data[0][0], 'layers.meta.commit_count')}
+                            'max': get_data_item(data[-1][0], 'layers.meta.commit_count')}
                  }
 
     print(html.template.render(metadata=metadata, test_data=tests, chart_opts=chart_opts))