power: qpnp-fg-gen4: Allow retry ESR fast calibration more than once

Currently, when the ESR fast calibration is enabled and ESR delta
interrupt doesn't fire within a stipulated period, a retry is
attempted to allow ESR fast calibration to run for a single ESR
delta interrupt. Instead, allow it again till the timer expires.
This can help with improving SOC accuracy.

While at it, reset delta_esr_count to 0 when user re-enable ESR
fast calibration.

Change-Id: I2a749c3e08bd45fc27d3edf9224adccb58610448
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>