power: qpnp-fg: Add features to support external charger

Add following optional features for qpnp-fg to work with external
charger:
  1) Ignore false negative isense as requested;
  2) Enable soft JEITA irq as requested and use it for hard JEITA
     detection.

CRs-Fixed: 991446
Change-Id: I3bc8f312de404e4bcade6382cab2f0bd340de88f
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>