drivers: bcl_pmic5: Add ibat scaling factor support for ibat conversion

For some pmic, based on pmic FG/QG ADC range, BCL Ibat scaling factor
needs to be changed. Add an optional devicetree property to choose
QG_ADC with 5A range. If this property is defined, ibat scaling
factor will be divided by two. By default ibat scaling factor will be
one corresponding to FG_ADC with 10A range.

Change-Id: I9f176f61a7187e5307943ee473e06bc9261c0a56
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>