power: qpnp-fg-gen3: support JEITA thresholds configurable runtime

Currently, JEITA thresholds are configured through the device
tree properties. Allow them to be configured runtime through
power supply properties.

Change-Id: Ie93c7e447a4f8ac793e6e324f7a0269dbc14c7e5
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>