smb-lib: report FULL regardless of charger presence

For a full battery, the driver currently reports battery full
only when the charger is online and switches back to reporting
discharging when charger is removed.

This is incorrect because a user might reinsert the charger
seeing discharging status right after he removes it only to
realize that the battery is full after he plugs it back.

So allow the full status to be reported even when no charger is
online.

Change-Id: I0c31e2fbe984420a6754e923cfc3abe77bc54991
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>