power: battery: smb5-lib: Introduce FCC Main Votable

Currently FCC of main charger is set based on a power supply property.
Introduce a new FCC MAIN votable to vote on setting the FCC of main
Charger. Defining FCC and FCC main votables allows us to independently
configure/specify the overall (target) FCC and the FCC requirement of
the main charger. Thus, helping in CP based designs where the main charger
runs with fixed FCC values. Reset the vote on charger removal.

Change-Id: I32a28b10a582167edcde904536735290fbfa2bc1
Signed-off-by: Sahil Chandna <chandna@codeaurora.org>