dt-bindings: qpnp-fg-gen4: Add properties to support SW based SOC scaling

Add qcom,soc-scale-mode-en, qcom,soc-scale-vbatt-mv, qcom,soc-scale-time-ms
properties to support SW based SOC scaling using filtered battery voltage.
This helps on aged batteries, where SOC calculated by FG can remain high
for low battery voltage.

Change-Id: I0fa462f98eedbb78a2ec6a2f8d49674e88875247
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>