hwmon: pm8xxx-adc: Update pa_therm mapping table

Inaccurate temperature readings are reported for
pa_therm when read from the apps. This is because
an inaccurate B constant was used while calculating
the voltage to temperature mapping table. Fix it
by generating the table using the correct B constant
for the thermistor.

Change-Id: I13f5dde11e1a3f51b7579de1fe924c162f2b31a1
CRs-Fixed: 374589
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>