iio: rradc: Add temperature compensation for die temperature

Add charger die temperature scaling coefficients based
on FAB ID. If FAB ID support is not available from the
REVID peripheral the driver does not report scaled
temperature for charger die temperature. Update temperature
compensation for PMIC die temperature.

Change-Id: I8864dccc1b53e70dac5d54129339e7224ec8ba67
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>