power: qpnp-fg-gen3: apply SOC linearization based on user input

Currently, SOC linearization is done when SOC masking feature is
enabled to spread out the drop in SOC across a wider range and
for better user experience. Make this configurable through a DT
property "qcom,linearize-soc" so that the user can enable it as
and when required.

Change-Id: Ic9f5f04f4e872d7804152c17206a8b204de3a9c1
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>