power: supply: qti_battery_charger: Handle generic notification

Charger firmware sends some battery related events with a generic
notification opcode. Handle such notifications as well to send
events up to the userspace.

Change-Id: Ia35fb7dbe56183d3c7c7a66b5f387b94072e6ed0
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>