power: qpnp-bms: enable ADC voltage notifications to wake up BMS

Use the ADC-TM to wake up the system and notify BMS if voltage
drops to dangerously low levels. The BMS will then hold a wakelock
and calculate faster to meet the 0% cutoff voltage requirement.

Also, use the ADC-TM to wake up the system and notify BMS if voltage
goes into the vddmax range. When battery voltage gets to this point,
charging will be in constant voltage mode.

After getting the notification, call power supply changed to notify
charger of the change in voltage state.

Since the vbat_sns readings that drive the ADC-TM voltage
notifications become invalid if battery is removed, unregister the
nofitications if that happens. Register the notifications if a new
battery is inserted.

CRs-Fixed: 480859
CRs-Fixed: 433840
Change-Id: I73cc6d712095dd4ac3506e1418d7c975ca263948
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>