power: battery: cleanup FCC stepper flow to handle override votes

Update following in the FCC stepper design:
- Skip stepping in case if override vote is applied on main's or
  parallel's FCC.
- In case of CP calculate the target FCC/ILIM based on maximum
  allowed ICL and FCC.

Also cache the userspace daemon's vote on main charger's FCC and
use it for all subsequent ILIM calculations, this is to ensure
across disable/re-enable of CP(due to hw faults/FCC) CP_ILIM is
always calculated based on override vote.

Change-Id: I548b4a99c11de9cd89b6a25f8c23180363db7a69
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>