leds: qpnp-leds-wled: configure AVDD TRIM voltage for AMOLED panels

Certain AMOLED panels may require voltage value to be configured
which is not within the voltage values allowable in WLED_OVP register.
In such cases, we may need to add/subtract the voltage value to obtain
the desired voltage value. Add support using TRIM register for the same.

Change-Id: I608a646233024b6b254df23d379ec9c8be277304
Signed-off-by: Abinaya P <abinayap@codeaurora.org>