icnss: Add support for power supply monitoring feature

Wlan platform driver registers to power supply framework
to receive a callback when any of battery parameters changes.
Wlan platform driver measures battery capacity/percentage once
it receives callback from power supply framework.Once
battery capacity/percentage reaches specific thresholds,
it indicates wlan fw to vote 3p3 ldo at a particular voltage
level.

Change-Id: I70b2a470bcdcef328f8721ac6755702883f331b3
Signed-off-by: Sandeep Singh <sandsing@codeaurora.org>