power: pm8921-bms: scale rbatt with temperature and soc

The rbatt was observed to change with battery temperature and the state
of charge of the battery. Update the BMS driver and the battery data
to include and use a rbatt table indicating its changes w.r.t temperature
and state of charge.

On similar lines provide api for other systems to query battery resistance.

Change-Id: I681675db537b70919e6e0437bd400ce53bf97096
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>