power: qpnp-fg-gen4: add support for ESR fast calibration

Add support for ESR fast calibration algorithm as per hardware
recommendation. ESR timers will be configured with a faster
period and the measured ESR will be used to feedback the FG
hardware so that the ESR can be measured quickly again. Once
the ESR fast calibration is done after a certain number of
measurements, ESR timers will be configured back with a default
or slow period and ESR delta interrupt will be kept disabled.

Also, change the ESR pulse threshold from 110 mA to 47 mA so that
ESR pulses can be qualified better.

Change-Id: I9fa58ff1efbdc1b8fedf94acc33a43a91a94fad1
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>