power: qpnp-fg-gen4: Cancel ESR fast calibration timer properly

Set esr_fast_calib flag to false after disabling ESR fast
calibration in the case of a debug battery so that alarm timer is
cancelled as expected.

Change-Id: Idb085e95c60ec0279851d007cb369d2902386082
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>