Add buildbot spec for Android One bots

BUG=skia:

Review URL: https://codereview.chromium.org/1517733002
diff --git a/tools/buildbot_spec.py b/tools/buildbot_spec.py
index d818518..b62fe61 100755
--- a/tools/buildbot_spec.py
+++ b/tools/buildbot_spec.py
@@ -209,6 +209,7 @@
     }.get(builder_dict['target_arch'], 'arm_v7_neon')
   elif builder_dict.get('os') == 'Android':
     return {
+      'AndroidOne': 'arm_v7_neon',
       'GalaxyS3': 'arm_v7_neon',
       'GalaxyS4': 'arm_v7_neon',
       'Nexus5': 'arm_v7', # This'd be 'nexus_5', but we simulate no-NEON Clank.