types: Convert ScaledOffset to double
types: Convert ScaledOffset to double

ScaledOffset is derived from incoming int64 using pow() and there
is a use case for having a fractional or negative ScaledOffset.
Since it's derived internally and applied internally this change
should have no impact on external interfaces.

Change-Id: I419e4de089d3845295157fff440c5d8e029e7c96
Signed-off-by: Emily Shaffer <a6e326c88a51217312e91af047fa468d2d7dea8f@google.com>
Tested: Ran ipmitool sensor list to check value sanity

openbmc/phosphor-host-ipmid,openbmc/phosphor-host-ipmid,openbmc/phosphor-host-ipmid