illumos gate

While working on #12954, I realized that past me had made a mistake that turned out not to matter too much. The ksensor framework has a notion of the granularity, being the units of the actual measurement and how to transform it into degrees, and the precision, being a +/- range that the sensor is accurate within. Hardware provides a register one can read which describes the actual precision which it calls the 'resolution'. In the original implementation in #11184 this was used as the 'granularity'. On almost all systems, this is one degree, so there was no impact from this and why when comparing the initial readings to the ipmi values on servers we didn't see any discrepancies. We should fix this while we're going through and doing #12954.