flimflam: crosmetrics: fix 5GHz frequency mapping

Correct the mapping of 5GHz frequencies to the enum value sent for
Network.Wifi.Channel.  Also add mappings for 5170, 5190, 5210, and 5230.

BUG=chromium-os:24342
TEST=new unit test

Change-Id: I33a62ee73cb33123083d394988c4ae6ae567192e
Reviewed-on: https://gerrit.chromium.org/gerrit/13103
Reviewed-by: Sam Leffler <sleffler@chromium.org>
Tested-by: Sam Leffler <sleffler@chromium.org>
Commit-Ready: Sam Leffler <sleffler@chromium.org>
2 files changed