hwmon: qpnp-adc: Add current and vbat compensation

Compensate the vbatt voltage for temperature variance
above 25degC. The vbatt readings improve with voltage
compensation based on the revision. Similar compensation
is applied to current which are based on the internal
or external rsense and the revision.

Change-Id: I3df8b918e6247041d651a0c9d819d77cc6af978c
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>