qcom: smb138x/smb1351: add support to expose BATFET configuration

Add support to expose how BATFET of main and parallel chargers
are configured. BATFET configuration is used for configuring
FCC of main charger.

Change-Id: I1fa47840dee08754425dc4540a61401313f0878a
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>