power: battery: Modify main charger max FCC limiting logic

Primary charger FCC configuration can be limited to an upper bound
due to inductor current saturation limitation. However, in case, when
the charge current from SMB1390 flows through the BATFET of primary
charger, SMB1390 charge current will also be bounded by the FCC limit,
therefore limiting the overall charge current.

Add support to disregard max FCC limit in case SMB1390 switcher is
enabled.

Change-Id: I1542f04e6a65f44b3a82411a1cbfeaa72e0649c7
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>