hwmon: pm8xxx-adc-scale: Change scaling function

Modify the scaling function routines for Battery temperature
and all channels whose units return milli-volts for voltage.

The Charger driver requires the Units of Voltage and temperature
in uV and 0.1 DegC according to the framework where all voltages,
currents, chargers, energies, time and temperature are in uV, uA,
uAh, uWh, seconds and tenths of degree Celsius unless otherwise
stated. In accordance with the above expected units, the scaling
functions are modified for all voltage channels and the Batt Therm.

This change fixes the XO Therm temperature scaling routine,
PA Therm and Batt id to use the ratiometric calibration.
XO Therm and PA therm units are returned as milli-degree and
degree Centigrade respectively.

Accordingly, update the clients of xoadc to handle this change in
units.

CRs-Fixed: 315797
Change-Id: I6fa3b808062563fef3b0e70cc694e3132421f735
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>