power: qpnp-fg: prevent ESR creep during taper charging

ESR is possible during taper charging with very high pulsed
current. To prevent that, apply the ESR strict filter values
when the charging mode is taper and apply the default values
to ESR filter when the device is not charging or not in taper
charging mode.

CRs-Fixed: 799678
Change-Id: Ief5d3b3fd0524e5428d730549fbd1d0677966e00
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>