hwmon: qpnp-adc-voltage: Add temperature compensation for PM8909

Add VBAT and OCV temperature compensation for PM8909
v1.1 SMIC parts.

The temperature compensation is required on top of
gain/offset calibration to compensate for variations
due to chip revision, manufacturer and temperature.

Change-Id: I1aa33dc57736c0ea6f4d50af3b9a58260f139790
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>