power: smb5-lib: Add vfloat condition for overcharge workaround

Make sure that the VBAT is indeed rising and is beyond the float
voltage before suspending the input for the battery-overcharge
workaround. The cc-soc increase may not be an accurate indicator
considering minor charge accumulation post termination due to ADC
inaccuracy while using external sense.

Change-Id: I7d3985c4e6632384ef04422bfad062d4707e0669
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>