Use visitor instead of pulling values directly

Sensor thresholds pull out an int64_t and immediately
assign it to a double. Use a visitor instead to avoid
the intermediate and add flexibility / saftey to type
readings.

Tested-By: Verifed sensor list still worked.
Change-Id: If49bf54ec1c0636b3549d433b86ecdbd1ea99b0d
Signed-off-by: James Feist <james.feist@linux.intel.com>
2 files changed